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NEW AND COMPLETE TREATISE 



AETS OF TANNING, CURETING, 



LEATHEE-D RES SING. 



mW AND COMPLETE TREATISE 



ARTS OF TANNINa CURRYING, 



LEATHER-DRESSING; 



COMPRISING ALL THE 

DISCOYERIES km IMPROVEMENTS MADE IN FRANCE, GREAT 
RRITAIN, AND THE UNITED STATES. 

EDITED FEOil NOTES AUD DOCUMENTS 

OF 

MESSRS. SALLEROU, GROUVELLE, DUVAL, DESSABLES, LABARRAQUE, 
PAYEN, RENE, DE FONTENELLE, MALEPEYRE, ETC. ETC. 

Professor H. JDUSSAUCE, Chemist, 

LATELY OF THE LABOEATORIES OF THE FRENCH GOVERNMENT, VIZ., THE MINING, BOTANICAL 

GARDEN, THE IMPERIAL MANUFACTURE OF THE GOBELINS, THE CONSERVATOIRE 

IMPLRIALE OF ARTS AND MANUFACTURES j PROFESSOR OF INDtfSTRIAL 

CHEMISTRY TO THE POLYTECHNIC INSTITUTE, PARIS. 



Illustrattb bg ®feo Pntrksb anb ^hdbt Wioaii ©ngrabings. 



PHILADELPHIA: 

HENEY CAKBY BAIED, 

INDUSTRIAL PUBLISHER, 406 "WALNUT ST. 

LONDON: 
SAMPSON LOW, SON & MARSTON. 

47 LtTDGATE HILL. 

1865. 



^,^f 



Entered according to Act of Congress, in the year 1865, by 

HENRY CAREY BAIRD, 

in the Clerk's Office of the District Court of the United States in and for the 
Eastern District of Pennsylvania. 



^ 



> 



PHILADELPHIA : 
COLLINS, PKINTER, 705 JATNE ST, 



TO 

HON. T. C. G. KENNEDY. 

SUPERINTENDENT OF THE CENSUS, WASHINGTON, D. C. 

My Dear Sir : 

Permit me to offer to you the following work, as 
a very feeble mark of gratitude for your unvarying 
friendship, the aid you have extended to me in the 
preparation of this volume, and a sincere testimonial 
of the high respect and esteem of, 
My dear sir, 

Your very obedient servant. 

And obliged friend, 

H. DUSSAUCB. 

New Lebanon, N. Y., May 1, 186-5. 



PREFACE. 



The art of tanning has for a long time consisted of a 
series of empirical operations, notwithstanding the fact 
that there is no art which is so dependent upon certain 
fixed principles, and on which chemistry exerts so great 
an influence. The processes followed in manufactories, 
in the past, have varied according to their localities; 
and have been transmitted from father to son, as heir- 
looms which they have had great scruples in abandon- 
ing or even touching. All new innovations were viewed 
w4th scorn, and rejected, even without experiment. 
When a workman had succeeded in producing good 
work, he believed he had attained the ne plus ultra of 
his art, and he would have believed he was unworthy 
of this title, if he could have been persuaded that he 
had yet many things to learn. 

Prejudice and routine are, nearly always, the faithful 
associates of ignorance and pride, principally with those 
who, accustomed to manual occupations, look upon as 
useless, and even banish as dangerous, those theories 
which alone can transform an empirical art into a 
rational one. For a long time yet, industry will be thus 
hampered and the benefits of science disregarded, and it 
is only by degrees that it will verify the arts. 

The closing years of the eighteenth century, and those 
of the nineteenth which have passed, have changed the 
ideas of manufacturers. Those who, located in the large 



Vlll PREFACE. 

cities, have been benefited by the help of science, have 
found imitators, and their innovations have gradually 
spread over the civilized world. 

The art of tanning was one of those of which the 
theoretical study was the most neglected; the first 
author who seems to have given his attention to it was 
M. Desbillettes, member of the Academic des Sciences, 
who in 1708 published a work on tanning, and in 1754 
furnished to the celebrated astronomer Delalande very 
good materials for his encyclopedical work on tanning 
arid currying. The researches of M. Delalande give 
exact processes, and a true picture of the method then 
followed. Guided by these works, several experi- 
menters, amongst whom we may mention MacBride, 
Pfeffer, and St. Real, published processes for the im- 
provement of the art of tanning, which, if they were not 
completely adopted, at least presented useful views. 
Such was the position of this art when one of the fellow- 
laborers of the illustrious Lavoisier, M. Seguin, proposed 
in 1774 to tan hides in from one to two or three months. 
The quality of the leather did not, however, correspond 
with the quickness of the operation. Notwithstanding 
this failure, the works of this chemist exercised a powerful 
influence on the progress of the art, principally after 
his chemical studies of tannin. Several English chemists 
adopted the ideas of Seguin, while others modified them, 
and discovered new processes. The art of tanning 
ceased to be an entirely empirical one, when chemistry 
began to help it, by the different works and researches 
of Gettliffe, the father and the son, Monier and Ray, 
Paillard Vaillant, Grouvelle, Duval Duval, Salleron, 
Dolphus, Fischerstroem, Payen, Kartsoff, Didier, J. 
Smith and J. Thomas, Trempe, Nenory, Tournal, Curau- 
deau, Conche, Poul, Labarraque, Leprieur, Bagnal, 



PREFACE. IX 

"Weldon, Dessables, Delbut, Boetger, Boudet, BerlinguGj 
Berendorf, Cox, Beringer, Vauquelin, Ogereau, Spilsburg, 
Kampfmeyer, Turnbull, Snyder, and others. 

We have here given the important facts, and the 
principles established by these investigators and authors 
on this subject. 

While gladly and fully acknowledging our indebted- 
ness for much matter to Professor Morfit's edition of De 
Fontenelle and Malepeyre's treatise, prepared some years 
since for the publisher of this volume, the present publi- 
cation may lay claim to being a new work, by reason as 
well of the numerous additions as by the considerable 
and important changes and improvements we have made 
throughout it. 

We take great pleasure in acknowledging our indebted- 
ness to those who have so kindly assisted us in our 
researches, and "v^uld express our particular obligations 
to. the Hon. J. C. G. Kennedy, Hon. D. P. HoUoway, 
D. Aldrich, Esq., Hatch, the Shaker Society of New 
Lebanon, etc. We have taken several articles from the 
two most important industrial publications of this 
country, the Slioe and Leather Reporter and the Scientific 
American, and desire here to acknowledge our obliga- 
tions to them. We have consulted nearly all foreign 
and home publications; in a word, we have neglected 
neither pains nor trouble to make this work a standard 
one. We trust it will answer the purposes for which it 
is designed, and our reward will then be found in the 
services we have rendered to the profession. 



CONTENTS. 



PAGfE 

Introduction 17 

Imports of hides at New York for the past sixteen years . . .21 

at New York for 1863 22 

" •" at Boston for 1863 24 

" " at Philadelphia . 26 

" " at Salem, Mass 26 

Leather produced in the United States in 1850 and 1860 . . .27 

Origin and Development of the Art of Tanning 31 

Parchment Dressing 38 

PAET I. 

CHEMISTEY OF TANNING. 

SECTION I. 

TAN AND TANNIN. 
CHAPTER I. 

PURE TANNIN. 

Chemical properties, 44. — Composition, 50. — Preparation, 50. 

CHAPTER II. 

IMPURE TANNIN. 

Chemical properties of impure tannin ; Preparation ; Varieties in the impure 
tannin, 53. — Preparation of tannin from nutgalls, 55. — Proust's pro- 
cess, 55. — Deyeux's process, 56. — Dize's process, 56. — Merat-Guillot's 
process, 56. — Bouillon-Legrange's process, 57. — Tromsdorff's process, 
57. — Serturner's process, 58. — Varieties of impure tannin, 58. — Tannin 
of catechu, 59. — Tannin of bark of trees ; Sumach ; Kino, 59. — Tannin 
which forms a bluish-black precipitate in solutions of a sesqui-salt of 
iron, 60. — Tannin which forms a green precipitate in the dissolution of 
iron, 60. 



XU CONTENTS. 

OHAPTEE III. 

ARTIFICIAL TANNIN. 

Properties, 61. — Composition, 62. — First variety, 62. — Second variety, 63. — 
Third variety, 63. — Preparation of a tannin from turf, 63. 

CHAPTER lY. 

TANNIN FROM VARIOUS SOURCES, 64. 

CHAPTER T. 

GALLIC AND ELLAGIC ACIDS. 

Gallic acid, 65. — Preparation, 66. — Scheele's process, 66. — Fiedler's process, 
66. — Braconnot's process, 66. — lire's process, 67. — Properties, 68. — 
Composition, 71. — EUagic acid, 71. 

CHAPTER YI. 

EXTRACTIVE, 73. 

SECTION II. 

TANNING MATERIALS. 
CHAPTER YII. 

TANNING SAPS — TANNING JUICES — KINO — CATECHU, 

Tanning saps, 78. — Sap of the beech tree, 79. — Tanning juices, 80. — Kino, 
80. — African kino, 81. — Jamaica kino, 82. — South American, Columbia, 
or Caraccas kino, 82. — Catechu, 82. — Cake catechu, 84. — Pegu catechu, 
84. — Bengal catechu, 84. — Bombay catechu, 84. — Gambir, 84. — Areca 
catechu, 85. 

CHAPTER YIII. 

EXCRESCENCES CONTAINING TANNIN. 

Nutgalls, 86. 

CHAPTER IX. 

, LEAVES — TEA — FLOWERS AND FRUITS — SEEDS AND BULBS. 

Leaves, 88. — List of tanning leaves, 89. — Tea, 90. — Flowers and fruits, 91. 
— Yalonia, 91. — Divi-divi, 93. — Of tanning flowers and flower tops, 94. 
— Seeds and bulbs suitable for tanning, 95. 

CHAPTER X. 

WOODS — ROOTS — BARKS. 

Woods, 96.— Roots, 96.— Dentelaria, 96.— Malefern, 96.— Rhatany, 97.— 
Marsh rosemary, 97. — Barks, 98. — Cinnamon, 101. — Sassafras, 102. — 
Birch bark, 103. — Chestnut bark, 103. — Horse-chestnut, 103. — Beech 



CONTENTS. Xlll 

bark, 103. — Lombardy poplar bark, 103. — Black thorn bark, 103. — Pome- 
granate bark, 103. — Ash bark, 104. — Elm bark, 104. — ^Cinchona bark, 
104.— Poison oak, 104.— Sumach, 104.— Willow bark, 106.— Tamarisk, 
107.— Hemlock bark, 107. 

CHAPTER XL 

OAK BARKS. 

European oaks, 108. — American oaks, 110. 

CHAPTER XII. 

BARKING OF THE TREES. 

Parts of the bark containing the most tannin, 112. — Age of the trees rela- 
tively to the richness of the barks in tannin, 113. — Barking and the 
most convenient time for it, 113. — Influence of seasons and place at the 
time of barking on the richness in tannin, 115. — Decrease in weight of 
smooth bark when exposed to the air, 115. 

CHAPTER XIII. 

PLANTS CONTAINING TANNIN USED AS SUBSTITUTES FOR OAK BARKS, 117. 

CHAPTER XIY. 

METHODS OF ESTIMATING THE TANNING POWER OF ASTRINGENT SUBSTANCES, 

Examination of barks, 123. — Chemical examination, 123. — R. "Warrington's 
process, 124. — Davy's process, 125. — Bell Stephens' process, 125. — 
MuUer's process, 126.— Method of Dr. D. W. Gerland, 131.— Table of 
the quantities of tannin contained in the principal tanning substances, 
134. — Comparative quantities of different tanning substances necessary 
to tan an equal quantity of leather, 136. 

CHAPTER XY. 

TAN OR POWDERED OAK-BARK. 

Bagnall's machine for chopping bark and fleshing hides, 138. — Weldon's 
mill for grinding oak-bark, 143. — Farcot's bark-chopping machine, 146. 
— Bourgeois's bark mill, 150. — Lespinasse's bark mill, 153. — Birely's 
mill, 159. 

CHAPTER XVI. 

TANNING EXTRACTS. 

J. Connel's concentrated extract, 161. — A. Steers's process, 162. — The 
Author's process, 163. 



XIV CONTENTS. 

SECTION III. 

SKIN. 

CHAPTER XVII. 

PROXIMATE PRINCIPLES OF LEATHER — STRUCTURE OF THE SKIN, 

Proximate principles of leather, 165. — Structure of the skin, 166. — ^Behavior 
of the epidermis and cutis with reagents, 167. 

CHAPTER XVm. 

CONSTITUTION OF THE SKIN. 

Composition of the skin, 169. — Fibrin, 169. — Gelatine, 171 . — Albumen, 172. 
CHAPTER XIX. 

THE PROPER TREATMENT OP HIDES AND SKINS — KINDS OF SKINS SUITABLE FOR 
TANNING — SALTING OF THE HIDES. 

Ox-hides, 177. — Calves' skins and kips, 178. — Horse-hides, 178. — Sheep- 
skins, 179. — Goat-skins, 180. — Deer-skins, 181. — Hog or pig-skins, 181. 
—Seal-skins, 181. — Porpoise-skins, 181. — Hippopotamus hides, 181. — 
Mode of salting hides, 181. 



• 



PAET II. 

TANNING. 

SECTION lY. 

PRELIMINARY TREATMENT OF SKINS. 
CHAPTER XX. 

WASHING AND SOAKING. 

Soaking of foreign hides, 186 

CHAPTER XXI. 

INFLUENCE OF THE WATER UPON THE QUALITY OF LEATHER. 

Rain water, 192. — Snow water, 192. — Spring water, 192. — River water, 193 
Lake water, 193.— Marsh water, 193.— Well water, 193. 

CHAPTER XXII. 

SWELLING OR RAISING OF THE HIDES. 

Lime process, 195. 



CONTENTS. XV 

CHAPTER XX III. 

STACKING OF THE HIDES, 198. 
\ 

CHAPTER XXIV. 

INCONVENlkNCE OF THE LIME PROCESS, 201. 

CHAPTER XXY. 

METHOD OF RAISING BY ACID, 202. 

CHAPTER XXVI. 

DEPILATION BY STEAM, 203. 

CHAPTER XXVII. 

DEPILATION BY CAUSTIC SODA, 204. 

CHAPTER XXVIII. 

DEPILATION BY SULPHURET OF CALCIUM AND SODA. 

Preparation of the hydrosulphate of lime, 206. 
CHAPTER XXIX. 

COOL SWEATING PROCESS, 208. 

CHAPTER XXX. 

RAISING BY BARLEY DRESSING, 210. 

CHAPTER XXXI. 

WALLACHIA LEATHER. 

Method of working the dressings, 223, — Bran dressing, 225. — Decomposition 
of the white dressings, 226. 

■ CHAPTER XXXII. 

RYE DRESSING, OR TRANSYLVANIA LEATHER, 227. 

CHAPTER XXXIII. 

RAISING BY SOUR TAN-LIQUOR. 

Preparation of the tan-liquor, 233. 

CHAPTER XXXIV. 

RAISING BY YEAST, 236. 

CHAPTER XXXV. 

WORKING ON THE BEAM, 237. 



XVI CONTENTS. 

SECTIOIsT V. 

TANNING PROCESS. 
CHAPTER XXXVI. 

TAN TATS. 

Wheat's patent vat, 244. 

CHAPTER XXXYII. 

HEALD's apparatus rOR| TANNING HIDES, 247. 

CHAPTER XXXVni. 

TIME NECESSARY FOR TANNING, 251. 

CHAPTER XXXIX. 

PROPORTIONS OF THE BARK USED, 252. 

CHAPTER XL. 

DRYING OF THE LEATHER, 253. 

' CHAPTER XLI. 

BEATING OF THE LEATHER, 257. 

CHAPTER XLII. 

BEATING AND ROLLING BY MACHINERY. 

Debergue's machine, 260. — Flotard and Delbut's machine, 264. — Berendorf 's 
machine for pressing hides, 270. — Cox's machine, 275. — Wiltse's rolling 
table, 277. — Seguin's machine to flesh and gloss leather, 279. 

CHAPTER XLIII. 

TISSUE AND QUALITY OF LEATHERS — THEIR DEFECTS AND THE WAY OP 
ASCERTAINING THEM.' 

Action of frost on leather, 282. 

CHAPTER XLIV. 

BELT LEATHER. 

How to manufacture cow-leather into uppers of a superior quality, 288 
CHAPTER XLY. 

TANNING OF CALF-SKINS, 291. 

CHAPTER XLYI. 

TANNING OF CALF-SKINS FOR THE PREPARATION OF WAXED CALF-SKINS. 
BY M. RENE. 

Classification of untanned calf-skins, 295. — Washings, 295. — Liming, 296. — 
Salted skins, 298. — Dried calf-skins, 298. — Dry calf-skins from foreign 
countries, 299. — River work, 300. — Operation first, 302. — Treatment 
with strong liquors, 316. — Dressing, 321. 



CONTENTS. XVll 

CHAPTER XLYII. 

TANNING OF GOAT AND SHEEP-SKINS. 

Bleaching of goatrskins, 326. — Coloring of whole sheep-skins, 327. 
CHAPTER XLYHI. 

MOROCCO LEATHER DRESSING — CORDOVAN LEATHER, 329. 

CHAPTER XLIX. 

TANNING OF HORSE-HIDES, 335. 

CHAPTER L. 

TANNING OF DIFFERENT SKINS, 337. 

CHAPTER LI. , 

TANNING OF THE SKINS OF SHEEP's LEGS FOR MAKING TUBES WITHOUT SUTURE, 
FOR COVERING THE CYLINDERS USED IN COTTON AND WOOL SPINNING. 

Leather bottles, 338. 

CHAPTER LII. 

RED LEATHER, 339. 

CHAPTER LIIL 

DANISH PROCESS, 339. 

CHAPTER LIV. 

CHEMICAL THEORY OF TANNING. 

Chemical researches on the art of tanning. By M. Knapp, 344. 

SECTION YI. 

IMPROVED PROCES'^ES. 
CHAPTER LY. 

SEGUIN's PROCESS, 352. 

CHAPTER LYI. 

PROCESS OF PREPARING GLOSSED LEATHER BEFORE THE TANNING OPERATION. 

Details of the work of the preparation of the leather, 353. — Hides, 353. — 
Smelting, 353. — Liming, 354. — Cleaning, 354. — Description of the 
apparatus, 354. — Tanning, 356. 

CHAPTER LYII. 

TANNING WITH MYRTLE, 356. 

CHAPTER LYHL 

TANNING WITH GEAPE-SKINS, 357. 



XVIU CONTENTS. 

CHAPTBE LIX. 

TANNING WITH STATICE, 358. 

CHAPTER LX. 

LEPRIEUR's TANNING PROCESS. 

Sugar of lead bath, 360. — Tan liquor baths, 360. — First series of infusions 
361. — Second series of infusions, 362. — Tanning in the vats, 363. — 
Quantities of tan employed for tanning 220 lbs. of leather, 365. 

CHAPTER LXI. 

d'arcet's process by the sulphate of sesqui-oxide of iron, 366. 

CHAPTER LXIL 

Newton's process, 367. 

CHAPTER LXIII, 

PREPARING DRY FLINT HIDES, 368. 

CHAPTER LXIY. 

process of tanning of H. C. JENNINGS, 370. 

CHAPTER LXY. 

BERENGER AND STERLINGUE's PROCESS, 371. 

CHAPTER LXYI. 

CORNIGUET's PROCESS OF SUBSTITUTING THE FRUIT OF THE PINE FOR THE BARK 

IN TANNING, 379. 

CHAPTER LXVn. 

YAUQUELIN's PROCESS. 

Description of the figures, 383. 

CHAPTER LXYIII. 

OGEREAU'S PROCESS, 390. 

SECTION YII. 

AMERICAN, ENGLISH, AND OTHER PROCESSES. 

CHAPTER LXIX. 

PROCESS OF TANNING WITH A DECOCTION OF OAK BARK, 391. 

CHAPTER LXX. 

Desmond's process, 393. 



CONTENTS. XIX 

CHAPTER LXXI. 

J. burbbidge's peocess with extract of oak bark and catechu, 393. 

CHAPTER LXXIL 

kleman's process, 394. 

CHAPTER LXXin. 

spilsbury's process by pressure, 396. 

CHAPTER LXXIV, 

M. w. drake's process, 398. 

CHAPTER LXXy. 

botch's quick process of tanning leather, 399. 

CHAPTER LXXVI, 

J. F. KNOWLIS'S PROCESS, 402. 

CHAPTER LXXYH. 

TANNING APPARATUS OF D. ALDRICH, OF ST. LOUIS, MO., 403. 

CHAPTER LXXYHI. 

TANNING WHEEL OF V. E. EUSCO, 413. 

CHAPTER LXXIX. 

NEW MODE OF TANNING SKINS BY A LIQUOR OF TAR AND SOOT. 

Preparation of the tan liquor, 417. — Preparation of the soot liquor, 418. — 
Preparation of the skins intended for leather, 418. — Preparation of 
leather for soles, 419. 

CHAPTER LXXX. 

. INDIAN METHOD OF PREPARING ELK-HIDES, 419. 

CHAPTER LXXXI. 

hatch's process OF TANNING, CALLED ILLINOIS FRENCH TANNING, 420. 

CHAPTER LXXXII. 

IRISH PROCESS, 425. 

CHAPTER LXXXni. 

PEOCESS OF MANUFACTURING LEATHER CALLED CUIRS A MURON, 425. 

CHAPTER LXXXIY. 

KALMUCKS' PEOCESS, 427. 



XX CONTENTS. 

CHAPTEE LXXXY. 

LEATHER MANUyACTURE IN TURKEY, 429. 

CHAPTER LXXXVI. 

J. hannoye's process, 433. 

CHAPTER LXXXVII. 

M. nossiter's process, 438. 

• 

CHAPTER LXXXVITI. 

squire's process, 442. 

CHAPTER LXXXIX. 

ENGLISH process FOR TANNING NETS, SAILS, AND ROPES, 443. 

CHAPTER XC. 

EXPERIMENTS IN THE TANNING OF CALF-SKINS WITH TAN, DIVI-DIVI, CATECHU, 
AND ELECAMPANE BARK. 

Oak bark, 444. — Divi-dj^vi, 445. — Catechu (terra Japooica), 445. — ^Elecam- 
pane bark, 445. 

CHAPTER XCI. 

TANNING HIDES, BY J. W. JOHNSON, 447. 

CHAPTER XCII. 

TURNBULl/S PROCESS, 447. 

CHAPTER XOni. 

S. SNYDEK'S PROCESS, 452. 

CHAPTER XCIT. 

H. HIBBARD's PROCESS. 

Preparation of the skins, 455. — Composition for tanning, 455. 
CHAPTER XCV. 

HEMLOCK TANNING. 

Process of tanning as performed at the Shaker Tannery, New Lebanon, 
N. Y., 458.- 

CHAPTER XCYI. 

HALTORSOn's PROCESS FOR RENDERING HIDES HARD AND TRANSPARENT, 461. 



CONTENTS. Xxi 

CHAPTER XCVII. 

TAWING. 

Kid leather, 463.— Imitation kid, 466. 

CHAPTER XCYIH. 

THE BEST METHOD OF TANNING SMALL LAMB-SKINS CALLED CHAMOIS, AND ESPE- 
CIALLY WHITE PELTRY FOR FURRIERS, 467. 

CHAPTER XCIX. 

NEW METHOD OP COLORING WHITE TAWED LEATHER, 469. 

CHAPTER C. 

QUICK TANNING. 

S. Dunseith's process, 473. — M. D. Kennedy's process, 474. — I. L. Wells' 
process, 475. — J. Cochran's process, 475. — W. R. Webster's process, 
475. — Bunting's process, 476. — Thompson's process, 476. — L. Robinson's 
process, 476. — T. G. Eggleston's process, 476. — A. Dietz's process, 477. 
— P. Daniel's process, 478. — D. Needham's process, 479. — R. Harper's 
process, 479. — A. Hill's process, 480. — J. Nuessley's process, 480. — 
M. A. Bell's process, 480. — Blet's process, 481. — Baron's process, 481. 
— Quick process, 482. — Guiot's process, 483. 

CHAPTER CI. 

RESIDUES AND PRODUCTS OF TANNERIES, 484. 



PART III. 

CUERTINa. 



SECTION VIII. 

GENERAL WORK OP THE CURRIER. 
CHAPTER CII. 

DIPPING, 488. 

CHAPTER CIII. 

SHAVING, 492. 

CHAPTER CIY. 

POMMELLING, 493. 

B* 



xxii' CONTENTS. 

CHAPTER CV. 

STRETCHING, 494. 

CHAPTER CVI. 

WORKING WITH THE ROUND KNIFE, 496. 

CHAPTER CVII. 

PREPARATION OF STRETCHED LEATHER, 498. 

CHAPTER CYIII. 

PREPARATION OF SLEEKED LEATHER, 499. 

CHAPTER CIX. 

COMPARISON OF SLEEK LEATHER WITH ALUM-DRESSED LEATHER, 502. 

CHAPTER ex. 

TALLOWED OR GRAINED LEATHER. 

Grain black ; how to improve it, 506. 

CHAPTER CXI. 

" WATER LEATHER, 510. 

CHAPTER CXII. 

OIL LEATHER. 

Oiled leather, 515. 

CHAPTER CXHI. 

WAXED LEATHER, 518. 

CHAPTER CXIY. 

ENGLISH HIDES, 518. 

CHAPTER CXV, 

WHITE LEATHER AND COMMON RUSSET, 521. 

CHAPTER CXYI. 

CURRYING OF CALF-SKINS — OILED CALF-SKINS, 522, 

CHAPTER CXYII. 

TALLOWED CALF-SKINS, 524. 

CHAPTER CXYHI. 

ENGLISH CALF-SKINS, 525. 



CONTENTS. XXlll 

CHAPTEE CXIX. 

1 

WAXED CALF-SKINS. 

Flesliing and shaving, 526. — Bleaching or Whitening, 542. — Graining, 545. 
— Mode of making the blacking and its applications, 547. — Finishing, 
550. 

CHAPTER CXX. 

GRAINED CALF-SKINS, 556. 

CHAPTEE CXXI. 

CALF-SKIN LEATHER FOR BELTS, 557. 

CHAPTEE CXXII. 

GREASING TANNED HIDES, 557. 

CHAPTEE CXXm. 

SATURATION OF LEATHER WITH GREASE, 563. 

CHAPTEE CXXIY. 

CALF-SKINS CALLED ALUMED SKINS, 564. 

CHAPTEE CXXY. 

F. JAHKEL's PROCESS FOR MANUFACTURING LEATHER FOR HARNESS-MAKERS, 569. 

CHAPTEE CXXYI. 

CURRYING OF GOAT-SKINS, 571. 

SECTION IX. 

RUSSIA LEATHER. 

CHAPTEE CXXVII. 

PROCESS OF MANUFACTURING RUSSIA LEATHER, 575. 

CHAPTEE CXXVIII. 

DISTILLATION OF THE EMPYREUMATIC OIL OF BIRCH-BARK FOR RUSSIA LEATHER. 

Fischerstroern's process, 578. — Another process, 579. — Grouvelle and 
Duval-Duval's process, 579. — Payen's process, 580. 

CHAPTEE CXXIX. 

NATURE OF THE ODORIFEROUS SUBSTANCE OF THE BIRCH-TREE BARK, 582. 

CHAPTEE C^XX. 

PREPARATION OF RUSSIA LEATHER, 583. 



XXIV CONTENTS. 

CHAPTER OXXXI. 

COLORING OF RED RUSSIA LEATHER, 584. 

CHAPTER CXXXII. 

EXTRACT FROM A MEMOIR ON THE PROCESS OF TANNING SKINS IN RUSSIA BY THE 
COUNT OP EARTSOFF, 586. 

CHAPTER CXXXIII. 

RED LEATHER, 590. 

CHAPTER CXXXIV. 

SHAGREEN AND PARCHMENT. 

Shagreen, 592. 

CHAPTER OXXXV. 

PARCHMENT, 595. 

SECTION X. 

PATENT LEATHER, 

CHAPTER CXXXVI. 

FABRICATION OP THE PATENT LEATHER, 600. 

CHAPTER CXXXVII. 

didier's process. 
White polished leather, 603. — Red polished leather, 603. — Blue polished 
leather, 604. — Yellow polished leather, 604. — Polished leather of leather 
color, 604. — Black lacquer for shoes and leather work, 604. — Process 
for varnishing leather for belts, &c., 605. 

SECTION XL 

WATER-PROOF LEATHER. 

CHAPTER CXXXVIII. 

PROCESS OF J. SMITH AND J. THOMAS, 606. 

CHAPTER CXXXIX. 

NENORY's preparation to RENDER LEATHER WATER-PROOF AND IMPERVIOUS. 

Preparation of siccative oil, 607. — Preparation of the elastic gum, 607. — 
Preparation of the compound* 608. — Process of using the composition, 
608. 



CONTENTS. XXV 

CHAPTER CXL. 

dean's process for rendering leather impervious. 

First composition, 608. — Second composition, 609. — Third composition, 
609. — Fourth composition, 609. — Application of the composition, 610. 

CHAPTER CXLI. 

different processes. 
Cheap method of making leather water-proof, 611. — Jenning's process, 611. 



PART IV. 

HUNGAKY LEATHER. 

SECTION XII. 

CHAPTER CXLII. 

grease and animal oils. 

Lard, 615. — Mutton suet, 616. — Beef tallow, 616. — Medullary beef tallow, 
616.— Fish oils, 616.— Dolphin oil, 617.— Porpoise oil, 617.— Different 
fish oils, 617. — Process by which to give to a mixture of different oils 
and greases the properties of fish oils, 618. — 'Process for rendering 
vegetable oils fit to take the place of fish oils, 618. 

CHAPTER CXLIII. 

RIVER WORK, 618. 

CHAPTER CXLIY. 

■ ALUMING the HIDES, 619. 

CHAPTER OXLY. 

SECOND ALUMING, 622. 

CHAPTER CXL VI. 

DRYING AND STRETCHING, 622. 

CHAPTER CXLVIL 

TREADING OUT THE HIDES, 623. 

CHAPTER CXLVIII. 

TALLOWING, 624. 



, I 



XXVI CONTENTS. 

CHAPTER OXLIX. 

FLAMING, 628. 

CHAPTER CL. 

EXPOSURE TO THE AIR, 629. 

CHAPTER CLI. 

WEIGHING. — MARKING. — PILING, 630. 

CHAPTER OLII. 

HUNGARY LEATHER MADE OF COW AND CALF-SKINS, 631. 

CHAPTER CLIII. 

HUNGARY LEATHER MADE OF HORSE-HIDES, 631. 

CHAPTER CLIY. 

M. KRESSE's PROCESS OP PREPARING BLACK HUNGARY LEATHER, 633. 

CHAPTER CLY. 

DEFECTS IN THE QUALITY OF HUNGARY LEATHER, 634. 

CHAPTER CLYI. 

uses of HUNGARY LEATHER, 635. 

CHAPTER CLYII. 

IMPROVEMENT OF M. CURANDEAU, 636. 



PAET Y. 

GUT-DRESSING. 



SECTION XIII. 

PREPARATION OP THE INTESTINES OF CATTLE, 

CHAPTER CLYIII. 

OPERATIONS FOLLOWED IN THE PREPARATION OF INTESTINES OF CATTLE. 

Description of the workshop, 638. — Scouring, 638. — Turning over, 639. — 
Putrid fermentation, 639. — Scraping, 640. — Washing, 640. — Insuffla- 
tion, 640. — Desiccation, 641. — Disinsufflation, 641. — Measuring, 641. — 
Sulphuration, 641.— Folding, 642. 



CONTENTS. XXVll 

CHAPTEE CLIX. 

DISINFECTION OF THE WOEK-SHOPS. — MODE OF SUPPRESSING PUTREFACTION, 642. 

CHAPTER CLX. 

gold-beater's SKIN, 643. 

CHAPTER CLXI. 

LATHE-CORDS, 644. 

CHAPTER CLXII. 

MANUFACTURE OF CORDS FROM THE INTESTINES OF SHEEP, 645. 

CHAPTER CLXni. 

DIFFERENT CORDS. 

Cords for rackets, 647. — Whip cords, 647. — Hatter's cords for bowstrings, 
648. — Clock-maker's cord, 648. 

CHAPTER CLXIY. 

CORDS FOR MUSICAL INSTRUMENT STRINGS, 649. 



PAET YI. 

DIFFEKENT KINDS OF APPARATUS USED BY LEATHER 
MANUFACTURERS. 

CHAPTER CLXY. 

IMPROVED MACHINE FOR ROLLING GREEN OR WET LEATHER. 

Operation, 659. 

CHAPTER CLXYI. 

MACHINES FOR FINISHING LEATHER, 661. 

CHAPTER CLXYII. 

LEATHER POLISHING MACHINE, 673. 

CHAPTER CLXYin. 

JACOB Perkins's machine for pommelling and graining, leather, 675. 

CHAPTER CLXIX. 

NISBET'S GROUNDING AND PUMICING MACHINE, 678. 



XXVlll CONTENTS. 

CHAPTER CLXX. 

EMBOSSING OF LEATHER. 

Bernheim and Labouriau's process, 682. — F. W. East's process, 686. 

CHAPTER CLXXI. 

degrand's machine for splitting and shaving leather, 687. 

CHAPTER CLXXII. 

gikaudon's machine for splitting and shaving leather, 688. 

CHAPTER CLXXIII. 

machines for splitting and shaving leather. 
Richardson's machine, 694. — Chapman's improved leather splitting machine, 
697. — Introduction of splitting machine into German heavy and upper 
leather tanneries, 699. 



THE 



ARTS OF TANNING, CURRYING, 



LEATHER-EEESSING. 



INTRODUCTION. 

The art of tanning is that by which animal skins are 
converted into leather, a product possessing certain char- 
acteristic properties, differing entirely from those of the 
same material, and eminently adapting it to the useful 
purposes for which it is employed. Those properties 
are of a physical nature, and vary with the kind of skin 
employed, and the modification of the process which it 
undergoes. Chemically considered, however, leather 
proper, whatever its kind, is a definite compound of tan- 
nin and gelatine, possessing the all-desirable requisites of 
durability, pliability, inalterability, insolubility in water, 
and great power of resisting the action of chemical re- 
agents. When mineral or earthy substances are used as 
the leather-making agents, the result is a compound of 
gelatine with the base employed, and is more or less in- 
destructible, according to the nature of the material and 
the circumstances under which the combination takes 
place. 

It is much to be regretted that so little has been done 
by science for the improvement of the art of tanning, 
2 



18 INTRODUCTION. 

although many years have elapsed since the chemical 
union of tannin and gelatine was first demonstrated ; 
discovery has not yet shown that abundant fruitfulness 
which it seemed to promise positively and almost imme- 
diately. It is true that a long step forward has been 
made, but has it not been effected by automatic rather 
than by natural movement ? by mechanical force rather 
than by scientific combinations ? In a word, is not the 
art of tanning in America almost as strictly empirical 
now as it ever was ? If the production of our tanneries 
has been increased and the time of their work shortened, 
it is not owing so much to the introduction of new prin- 
ciples and to scientific theorizing as to the use of improved 
apparatus for facilitating old processes. Take away our 
bark and hide-mills, improved vats, and other construc- 
tions, and our steam power, turn us out of doors to work 
amongst the rude contrivances of a hundred years ago, 
and would the result of our labor show an extraordinary 
gain over those of our predecessors ? 

The modern appliances, of which American tanners 
boast, are certainly ingenious and praiseworthy, and we 
would not be understood to depreciate their importance, 
or to slight the intelligent enterprise of which they are 
the offspring. But we wish to record and to direct 
attention to the fact that in tanniug, as in other occupa- 
tions, the habits of the American mind lead to invention 
rather than to discovery. Now, in many other occupa- 
tions, the fertile invention of our countrymen may insure 
perfect success; but in tanning it cannot; for here in- 
vention is only the servant of discovery, and must follow 
instead of preceding it. It is skill, not force, chemical 
combination, not steam power, which is principally to 
accelerate and cheapen the process of tanning ; and the 
sooner the trade acts on this conviction, which every 



INTRODUCTION". 19 

day's experience ought to strengthen, the better. If they 
can supersede our present machinery by the discovery 
of more effective and economical methods, it will furnish 
causes for congratulation and none for mourning. They 
must aim to be good chemists, as they are already .good 
mechanics. With the analytical taste of the French and 
Germans superadded to their over-ingenuity and energy, 
what results might not be expected from their studies ? 
The field to be explored is a broad one. Long as the 
art of tanning has been known to the world, not one 
step in its practice seems to be complete. There is still 
room for inquiry after tanning materials, and still a 
doubt whether tannin, or what is equivalent to tannin, 
may not be produced in quantity by artificial means. 
The hide itself should be examined and analvzed at 
every stage of its manufacture. Its structure cannot be 
too minutely scrutinized ; its preliminary preparation is 
a problem ; the nature of gelatine is a study ; the manu- 
facture of ooze, simple as it appears, is not uniform ; the 
proper consistency and strength of the liquor is yet to 
be graduated and fixed. Most of all, the union of the 
tannin and the gelatine in the interior fibres is to be 
critically observed and facilitated by every possible 
means. The object is, of course, to produce leather in 
less time and at less cost than heretofore. 

To these remarks the tanner will probably reply that 
he has neither taste, time, nor means to employ in 
chemical experiments. But if this is so, he can at least 
join with his brethren and endeavor with them to effect, 
by concerted action, that which it may be impossible for 
a single individual to accomplish. It is worth while to 
inquire whether our associations might not advanta- 
geously employ educated chemists to unlock for them 
the secrets of nature. 



20 INTRODUCTION. 

There is no denying that ignorance is the real bar to 
our progress ; that our pathway to success winds up the 
hill of science. If we cannot travel it alone, we should 
secure guides, and accept whatever assistance is at hand. 

Leather is employed for many useful and ornamental 
purposes, and numerous are its applications to various 
branches of industry. Besides its extensive use for 
covering for the head and feet, wearing apparel, saddles, 
harness, etc., it is largely employed for the embellishment 
of objects of taste and ornament. 

Independently of the direct importance of the leather 
trade, it exerts a very decided incidental influence in 
developing the resources of a country, by giving value 
to certain materials used in, and resulting from the 
manufacture. Besides the immense quantity of bark 
which it consumes, it furnishes the raw material which 
gives employment to thousands of artisans. Even the 
waste material of slaughter-houses, tanneries, currier's 
shops have important applications ; the horns serving 
for the manufacture of combs, buttons, and umbrella 
furniture ; the hairs for plasterer's use, the spent lime 
for the farmer, the skin clippings for the glue boiler, 
etc. etc. 

The following statements will suffice to give an idea 
of the vast extent and rapid increase of the trade in 
leather in the United States. 



INTRODUCTION. 



21 



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22 



INTRODUCTION. 



Imports of Hides at the Port of 
Compiled from the Weekly Official Tables 



FOREIGN. 



African 

Bahia , 

Buenos Ayres 

Carthagena 

Chagres 

Curacoa 

East India 

Honduras 

Maracaibo 

Maranham 

Mexican 

Monte Video 

Orinoco 

Para 

Porto Cabello 

Porto Platte 

Rio Grande 

Rio Hache 

Savanilla 

Sierra Leone 

West India, &c„ 

Sundry Central American.... 

Sundry South American 

From Antwerp 

From Bremen 

From Genoa 

Fi'om Hamburg 

From Havre 

From Liverpool 

From London 

From Marseilles 

Sundry Foreign 

Total Foreign, 1863 

1862 

1861 

" " 1860 

" " 1859 

DOMESTIC. 

California 

New Orleans 

Texas 

Sundry Coastwise 

Railroad 

Total Domestic, 1863 

" " 1862 

" " 1861 

" " 1860 

" " 1859 

Total For. & Dom'tic, 1863 
" " " 1862 
" " " 1861 
" " " 1860 
" " " 1859 

Calcutta, &c., in bales 



Jau'y. 



3,426 



17 



,632 
,709 

"56 

"697 



,435 
,915 



20 



6,545 



581 

847 



6,703 



,750 
,500 



79,816 

77,992 

81,581 

188,875 

184,263 



2,564 

10,627 
14,940 



28,131 
24,562 
55^546 
83,237 
82,091 



107,947 
102,554 
137,127 
252,612 
216,354 



Feb'y. 



15,200 

20,301 

25,611 

73 

227 

"'343 

i','648 

14,580 

26,123 

11 

5,585 

5"203 

5,089 

3"697 
6,890 



3,000 
6,122 

"581 



140,284 
61,297 

133,014 
87,211 

120,570 



2,081 

"264 
6,609 



8,954 
46,283 
49,353 
49,825 
36,511 



149,238 
107,580 
182,377 
137,036 
157,081 



March. 



2,113 

4,476 

18,703 



276 

1,297 

10 



8,719 

"100 

11,393 

i"l76 

3"436 
4,951 
4,252 
4,896 



9,099 
1,194 
3,615 



79,706 

106,275 

58,114 

91,443 

175,563 



21,762 
693 

4,(388 
4,667 



31,810 
18,794 
45,586 
68,498 
80,063 



April. 



7,033 

20,915 

1,227 

i',738 

"'49 



5,532 
27,595 

"173 
1,910 

25,903 



4,669 

20,087 

3,480 



7,117 



1,746 
8,433 

"' 31 



137,638 
62,791 
87,763 
51,212 

200,973 



509 

15,650 
11,440 



27,599 
46,364 
55,048 
86,512 
46,988 



111,516 165,237 
125,069 109,155 
103,700i 142.811 
155,941,137,724 

255,6261 247,879 



May. 



414 

7,323 

91,930 



329 



5,809 
26,001 
20,697 

2,412 

44,870 



2,130 

4,463 

990 



207,368 

158,173 

58,656 

58,285 

216,413 



36,059 

"'913 

1,877 



38,849 
36,143 
64,948 
82,990 
40,730 



206,217 
194,316 
123,604 
141,275 

257,178 



2,738 
70,191 

"159 



7,777 
15,000 
12,051 

1,075 



12,895 

3,362 

i"619 

7,336 

123 

3,060 



101 



137,487 

108,948 

52,367 

73,322 

158,242 



2,500 

li','999 
2,445 



16,944 
38,057 
7,363 
70,600 
36,834 



114,431 

147,005 

59,730 

44,082 

95,076 



INTRODUCTION. 



23 



New York, for the Tear 1863. 
of " The Shoe and Leather Reporter." 



August. 


Septem'r. 


October. 


Novem'r. 


Decem'r. 


Total 


Total 


Total 


Total 


Total 












1863. 


1862. 
24,028 


1861. 


1S60. 


1S59. 






7,593 




4,920 


59,915 


35,803 


26,542 


26,690 


2,851 




12,716 




221 


58,215 


86,616 


4,000 


130 


47,508 


24,581 


13,748 


21,862 


17,162 


54,587 


895,998 


303,552 


146,606 


263,864 


470,393 




873 


856 


182 


2,266 


9,849 


15,684 


6,532 


3,379 

77,582 


27,821 
97,663 




496 




964 


89 


5,808 


3,248 


8,088 


5,680 


8,043 




402 




400 




2,159 




18,208 


15,718 


11,783 


111 






365 




1,734 


3,925 


2,846 


20,781 




433 


1,221 


2,833 


500 


1,886 


11,756 


12,498 
15,288 


25,079 

2,208 


42,870 
8,087 


46,324r 
22,219 


10,382 


603 


6,947 


6,011 


3,266 


72,564 


51,538 


34,288 


24,684 


66,241 


15,661 


5,525 




30,588 


55,510 


259,790 


82,688 


54,243 


82,264 


184,996 




15,804 




37,363 


15,957 


127,995 


160,780 


139,879 


121,176 


282,877 


3,632 




6,'350 


... 


1,051 


15,765 


28,575 


5,512 


4,667 


16,800 


6,147 






9 




20,696 


38,625 
5,146 


34,390 
7,320 


■ 24,352 
16,936 


25,860 
18,606 


9,504 


7,993 


... 


13,144 


14,862 


170,445 


17,3,248 
1,872 


46,082 
857 


138,888 
2,544 


178,641 
12,808 


442 






i,'598 




13,582 


18,181 
18,421 


5,994 
24,300 


49,218 
9,120 


28,547 
36,523 


1,783 


849 


1,059 


4,319 


4,114 


40,051 


25,516 


9,319 


12,655 


34,117 


8,800 


4,114 


5,388 


4,097 


4,630 


82,481 


74,447 


38,263 


16,427 


31,138 






903 






9,748 


18,564 


42,421 


10,312 


10,932 












4,896 


2,190 


5,092 


1,985 


6,552 






... 






9,703 


28,504 












... 






10,177 


28,958 
425 


2^986 




49^030 


... 






971 




16,192 


26,859 


6,083 




24,369 












4,690 


4,249 


7,408 


7,068 


42,077 


... 


... 


1,030 


2,500 




17,078 


6,841 


1,020 




11,860 
19,368 


... 








1,806 


2,834 


20,484 


4,169 


5,913 


62,840 


84,327 


51,688 


57,587 


120,173 


164,565 


CD 










132,802 


118,110 


118,441 


60,216 


104,101 


o 


1,219,950 








83,806 


21,781 


89,897 


25,832 


77,9:-i5 




♦ 


713,962 






43,640 


99,667 


57,217 


53,433 


96,416 








992,622 




154,271 


181,086 


71,603 


220,248 


121,881 










1,852,856 




11,458 




22,109 


27,584 


140,825 


297,907 


186,956 


169,150 


160,542 


. 266 










8,637 


9,184 


50,704 

74,258 


92.769 
212,769 


69.498 
101,147 


6,407 


24,332 


31,115 


11,938 


20,150 


146,937 


142,884 


118,788 


158,844 


122.427 


1,702 


1,206 


3,139 


1,112 




50,668 


92,249 


43,764 


90,103 


90,321 


8,375 


36,996 


34,254 


35,159 


47,734 


346,562 








25,566 


64,403 


58,869 


60,980 


52,174 




542,224 








22,891 


3,916 


60,657 


30,074 


27,567 






474,265 






33,747 


32,422 


188,628 


97,311 


51,860 








723,685 




26,741 


37,589 


17,458 


67,608 


34,068 










541,935 


92,702 


88,684 


91,791 


155,382 


172,299 


00 










158,368 


182,513 


176,810 


121,196 


156,275 


lO 


1,762,174 








56,207 


25,697 


100,154 


55,402 


105,502 


t^ 




1,188,243 






77,393 


136,089 


100,845 


150,744 


147,820 








1,716,257 




181,011 


218,675 


89,081 


287,851 


155,941 










2,397,791 




158 


100 


558 




866 


646 


1,724 


2,094 


823 



24 



INTRODUCTION. 



Imports of Hides at the Port 
Compiled from OfiBcial Sources for 



rOEEIGN. 


Jan. 


Peb. 


March. 
4,900 

2l',131 

l",878 


April. 


May. 


June. 


July. 


Bahia 


Il",'i50 
1,037 

11,315 

1,030 

105 
. 365 


6,853 

13,'360 
"28I 


30,467 

24,054 
4,000 
1,699 


5,583 

856 

4,936 

17, 440 

"'25 
"100 


1,003 

... 

l','628 


2,000 


Buenos Ayres 


14,788 


Cape of Good Hope 




Chili 




East India 




Manila, Singapore and Pe- 
nang Buffalo 




Manila, Singapore and Pe- 
nang Cow 




Sandwich Islands 




Sierra Leone 


8,781 


Other African 


12,641 


Truxillo 


2,463 


West Indies 


200 


From England 












Total Foreign, 1863 


25,002 

7,388 

4,381 

31,668 

13,167 


20,494 

14,155 

3,871 

4,893 

12,589 


27,909 
13,100 
17,864 
38,489 
39,689 


60,220 

17,208 

3,696 

5,526 

29,513 


28,940 
38,853 
49,803 
40,764 
30,023 


2,631 

44,965 

2,017 

6,600 

43,006 


40,873 


<' " 1862 


11,790 


« " 1861 


1,027 


" " I860 


10,462 




19,554 




DOMESTIC. 
Baltimore 


"397 

"772 
790 

27,032 


15,605 

2,486 
2,576 
3,015 
1,348 

24,738 


4,279 

"687 
199 

13,811 


6,173 
"715 

13,943 


600 

3,171 
1,000 

10",'l'83 


"618 

4,"iii 

1,840 
15",854 




California 


11,154 


Charleston 




Mobile 




New Orleans 


866 


New York 




Philadelphia 




Portland 


379 


Savannah 




Southern 




Texas 




By Rail 


13,371 




Total Domestic, 1863 

" " 1862 

1861 

" " 1860 

1859 


28,991 

9,642 

9,355 

27,303 

62,933 


49,768 
12,415 
13,288 
17,477 
28,208 


18,916 
12,183 
14,110 
24,377 
28,926 

46,825 
25,283 
31,974 
59,866 
68,615 


20,831 
7,680 
13,698 
40,804 
39,960 

81,051 
24,888 
17,394 
56,030 
69,473 


14,954 
12,792 
6,532 
26,400 
51,193 

43,894 
51,645 
56,335 
67.164 
11,426 


22,423 
12,227 
1,000 
23,697 
24,630 


25,770 

5,649 

217 

7,843 

21,503 


Total For. & Dom'tic, 1863 

1862 

1861 

1860 

" " " 1859 


53,993 
17,030 
13,736 
58,971 
76,260 


70,262 
26,570 
17,159 
22,370 
40,792 


25,054 
57,192 
3,017 
60,292 
67,736 


66,643 
17,439 
1,274 
18,305 
41,057 


CALCUTTA STOCK, &c. 
Buffalo (bales) 


395 
511 
485 
110 


897 
21 

642 


176 
148 

481 
258 


160 
260 
249 


*186 


449 
23 

134 
95 

701 




Cow 




Goat 


753 


Sheep 


896 


Calcutta via England.... 








Total Calcutta (bales) 


1,501 


1,554 


1,063 


669 


186 


1,649 



INTRODUCTION. 



25 



of Boston, for the Tear 1863. 
" The Shoe and Leather Reporter." 



August. 


Sept. 


Oct. 


Nov. 


Dec. 


Total 
1863. 


Total 
1862. 


Total 
1861. 


Total 
1860. 


Total 
1859. 


4,200 
12,042 

4,900 


"295 


2,*6oo 

1,155 

17,700 

6,600 

"207 

... 


4,000 
348 

5,424 
6,376 

16,148 
4,080 

7,916 
3,507 


6"430 

2,600 

2,595 

11,025 

19,410 

1,539 

4,256 

14,581 


10,200 

87,783 

1,913 

12,717 

6,055 

119,205 

31,912 

5,192 

432 

6,206 

746 


80,'517 
2,462 
7,299 
4,142 

12,500 

79,601 

6,411 
2,104 

8,785 
13,550 


19,'814 

250 

4,108 

12,386 

5,209 

7,255 

38,046 

5,546 

811 

3,212 

1,660 


62,629 

8,568 

23,327 

12,159 
15,287 
8i','732 

6, "7 13 

388 
10,908 
31,325 


95','730 
12,189 
17,055 

4,584 
12,263 
24/000 

2,323 

3,685 
59,256 
60,000 


20,332 
6,964 
13,972 
12,543 
23,563 


295 

22,414 

50 

23,620 

50,296 


27,662 

26,761 

78 

9,585 

14,861 


281,531 


204,996 


98,298 


202,972 


291,729 


"ioo 

103 
10,979 


9,'891 

i",ioo 

1,390 
870 
734 

16,349 


4,'943 

6,297 

'954 

"310 

2l",'374 


598 
11,373 

l",434 
423 

"102 

19,*507 

33,437 
50,075 

18,478 
27,860 


6,976 

3,049 
601 

25,305 


1,198 
44,337 

29"810 
5,990 
9,555 
7,162 

"310 

212,446 


5,684 
11,375 

18,'008 
15,450 
12,685 

1,646 

... 

... 

120,815 


4,249 

4,363 

27,621 

9,829 

862 

12,399 

3,098 

2,879 

■ 4,813 

120,888 


33,281 

""856 
10,596 

77,957 

"'490 
12,141 

6,067 
13,218 
20,031 

45,082 


24,805 

2,370 
13,587 
95,052 
29,605 

1,686 
14,468 
12,269 
21,595 

7,709 
112,159 


11,182 
10,785 
1,708 
12,608 
17,772 


30,334 

3,177 

504 

12,329 
9,428 


33,878 

31,060 

8,732 

4,221 

5,825 


35,931 
17,978 
889 
17,241 
21,052 


326,415 
607,946 

2.764 
1,353 
4,137 
2,303 

58 

10,615 


185,663 
390,658 

704 

2,128 
803 

'"612 

4,247 


190,951 


230,388 


339,235 


31,514 

17,749 
15,680 
25,151 
41,275 

'"68 


30,629 
25,591 
554 
35,940 
59,724 

120 
165 
379 
101 


61,540 
57,811 
8,810 
13,806 
20,686 

'"eo 

12 
3 

58 


49,585 
54,155 
31 
23,391 
31,367 

573 

165 

1,036 

141 


46,956 
17,978 
889 
21,491 
35,633 

"3.54 
57 


289,249 

2,087 

1,333 

1,336 

36 

4,792 


43,336 

2,080 

1,772 

1,867 

2 

5,721 


638,984 

3,583 

3,664 

2,996 

136 


68 


765 


133 


1,915 


411 


10,378 



26 



INTRODUCTION. 



Imports of Hides at Philadelphia. 
The following table exhibits the foreign importations, 
also the arrivals coastwise, of hides at the port of Phila- 
delphia for the past ten years. 

Years. 
1854 
1855 
1856 
185T 
1858 
1859 
1860 
1861 
1862 
1863 

The foreign importations in 1863 amounted to 53,109 
hides, and were divided as follows : — 



Foreign. 


Coastwise. 


Total. 


174,597 


10,451 


185,048 


156,102 


12,300 


168,402 


109,755 


9,399 


119,154 


125,180 


22,320 


147,500 


101,258 


33,200 


134,458 


128,029 


29,400 


157,429 


100,250 


8,730 


108,980 


65,271 


6,254 


71,525 


98,183 


11,913 


110,046 


53,109 


11,724 


64,833 



Porto Cabello and Caraccas . 


'. 


29,645 


Pernambuco 


14,058 


African 


6,258 


Rio Grande 


1,680 


West India 


1,473 




53,109 


Bundles of deer, goat, and sheep-skin 


. . 70 


Dozens " " " " . . 


. 649 


ORTS OF Hides at Salem, Mass., for 


THE YEAR 1^ 


Zanzibar 


42,825 


West Coast of Africa 




25,789 


Cayenne . . . . . 




2,518 


New York .... 




120,403 


Total, 1863 .... 


191,535 


" 1862 . . . . ^ 




162,281 


" 1861 . . . . ' 




184,701 


" 1860 .... 




318,986 


" 1859 .... 




430,774 


" 1858 .... 




424,000 



INTRODUCTION. 



27 



Below will be found an abstract from the Preliminary 
Keport of the Eighth Census, showing the amount of 
leather produced for the years 1850 and 1860 respectively, 
also the quantities furnished by each State during the 
same period. The tanners of the United States produced 
in 1850, exclusive of morocco and patent leather, goods 
to the value of $37,702,333, and in 1860 the product 
reached $63,090,751, being $25,388,418 greater than 
during the corresponding period of 1850. The largest 
producers of leather are, in their order. New York, 
Pennsylvania, and Massachusetts. The former turning 
goods to the value of $20,758,017, the second, $12,491, 
631, and the last $10,354,056, being an increase in the 
three States of $10,955,347; $6,195,268 and $4,681,497 
respectively on an aggregate increase of $21,832,112. 

We can have no better evidence of the immense 
benefits of the leather trade to the commerce of the 
entire country than is manifested by the growth and 
increase of this single article of production, as set forth 
in the' following -table during the ten years ending June 
1, 1860, and the exhibit of 1850. 



states and Value of product 


Value of product 


Per cent. 


Territories. 


in 1850. 


in 1860. 


increase. 


Maine 


$1,101,299 


$2,011,034 


18.2 


New Hampshire 


944,554 


1,933,949 


104.7 


Yermont 


'640,665 


1,000,153 


56.1 


Massachusetts 


5,672,559 


10,354,556 


82 3 


Rhode Island 


133,050 


80,897 


Decrease 


Connecticut 


775,325 


953,782 


23.0 


atal N. E. States. 


9,867,452 


16,333,871 


66.6 



28 



B 


. INTRODUCTION. 




states and 


Value of product 


Value of product 


Per cent. 


Territories. 


in 1850. 


in 1860. 


increase. 


JSTew York 


9,802,670 


20,758,017 


111.7 


Pennsylvania 


6,296,363 


12,491,631 


98.4 


New Jersey- 


1,269,982 


1,297,627 


2.1 


Delaware 


213,742 


37,240 


Decrease 


Maryland 


1,426,734 


1,723,033 


17.2 


Dist. of Columbia 56,000 


37,000 


Decrease 


Total Mid. States. 19,065,491 


36,344,548 


90 7 


Ohio 


2,110,982 


2,799,239 


32.6 


Indiana . 


750,801 


800,387 


6.6 


Michigan 


401,730 


574,172 


42.4 


Illinois . 


337,384 


150,000 


Decrease 


Wisconsin 


181,010 


498,268 


175.2 


Minnesota 




11,400 




Iowa 


24,550 


81,760 


23.3 


Missouri 


366,361 


368,826 


.6 


Kentucky 


1,108,533 


701,555 


Decrease 


Kansas . 




850 




Total W. States. 


5,281,351 


5,986,457 


13.3 


Utah 




93,255 




California 




223,214 




Oregon , 




14,500 




Washington 




17,500 




Total P. States 


351,469 




Virginia 


927,877 


1,218,700 


31.3 


. N. Carolina 


363,647 


313,020 


Decrease 


S. Carolina 


. _ 282,399 


150,985 


Decrease 


Georgia 


. " 403,439 


393,164 


Decrease 


Alabama 


344,445 


340,400 


Decrease 


Louisiana 


78,085 


47,000 


Decrease 


Texas 


52,600 


123,050 


132.0 


Mississippi 


241,632 


223,862 


Decrease 


Arkansas 


78,824 


115,375 


46.3 


Tennessee 


804,631 


1,118,850 


38.9 


Total S. States 


3,777,579 


4,064,407 


13.^ 


Aggregate in U. 


S. 37,791,878 


63,090,751 


66.9 



INTRODUCTION". 29 

The production of leather is a leading industry of 
much importance to the agriculturist and stock raiser, 
as well as to the commercial interests, inasmuch as it 
consumes all the material supplied by the former, and 
feeds an active branch of our foreign import trade. In- 
cluding morocco and patent leather the aggregate value 
produced in the Union in 1860 exceeded sixty- seven 
millions of dollars. , 

If we add to the sum total of this manufacture the 
aggregate value of all the allied branches into which it 
enters as a raw material, or take an account of the capi- 
tal, the number of hands, and the cost of labor and 
material employed in the creation and distribution of its 
ultimate products, it is doubtful if any other department 
of industry is entitled to precedence over that of leather.* 

The principal steps in the manufacture of leather are — 

1st. The loashing and soahing for the purpose of 
cleansing and softening the skins and preparing them 
for — 

2d. The depilation or removal of the hair. This is 
effected by the use of lime, or other substances, which 
destroy, dissolve, and soften the bulbous roots of the hair, 
and thus facilitate their removal by mere mechanical 
scraping with a blunt-edged knife. During this part of 
the process another important end is generally accom- 
plished in the swelling of the tissues, and their prepara- 
tion for the more complete and easj^. absorption of the 
tanning principle. The primitive mode of removing the 
hair was that of shaving it off with a knife, but the use 
of lime for this purpose was known even among the early 
Egyptians. When the rationale of the depilation is 
better understood by practical tanners, the slow and 

* Preliminary Report on the Eighth Census, 1860, by Jos. C. Gr. 
Kennedy, superintendent. 



30 INTRODUCTION. 

inconvenient process of depilation by means of lime will 
probably give place to more effective, rapid, and eco- 
nomical methods, such as the use of the hydrosulphuret 
of calcium. 

3d. Tanning. This step consists in promoting the combi- 
nation of the gelatinous tissue with tannin b}'^ immersing 
the softened and unhaired skins in an infusion of oak 
bark, or other substances containing tannin. The tan- 
ning influence is, probably, not exerted solely by the 
tannin, but also partly by the extractive matter, more 
or less of which always exists in tanning material. 
During the soaking, the epidermis of the skin disappears, 
and the tissue of the latter is gelatinized, and thus pre- 
disposed to chemical union with the tannin. This 
gelatinization of the tissue is all essential, and is pro- 
moted doubtless by the gallic acid fermentation of the 
tanning material. This is the more probable, since the 
same effect may be produced by the use of very dilute 
acetic and sulphuric acids, and since gallic acid has no 
primary or direct influence on the tanning. Since ex- 
posure to moisture, to air, and a temperature of 77° to 
86° are the requisites for this fermentation, which is 
developed by the action upon tannin of a ferment which 
is always present in tanning material, converting it into 
gallic acid. In consequence of this change, the pro- 
longed exposure of the liquor diminishes its tanning 
power. 

4th. Drying, rolling, and other operations intend/ed to 
perfect the quality and appearance of the leather. 



INTRODUCTION. 31 



ORIGIN AND DEVELOPMENT OF THE ART OP 

TANNING.* 

Upon the conviction that it will be agreeable to all 
in the trade to possess authentic data of an art, the 
practice of which is their vocation, and to follow its 
gradual development ah initio, we beg leave to present 
our readers with the following faithful sketch of the 
gradual rise and progress of the art of tanning, and we 
shall take pains to carefully collect all other notices on 
this subject of interest and value to the craft, and as a 
retrospect of its history. 

The origin of the tanner's art is lost in antiquity ; but 
it is supposed to have been an oriental invention; at 
least it was earlier brought to a state of perfection in the 
East than in Europe. 

According to Chinese authors, it was their ruler, Schin- 
fang, who taught them to prepare the skins of animals, 
and to remove the hairs with wooden rulers. Pliny as- 
cribes the invention of tanning to Tyckias of Boeotia ; 
but this is also uncertain. At t^iat time those who first 
introduced anything into a country generally received 
the credit of having invented it. The use of the skins of 
animals for clothing was known in the remotest ages, 
and but moderate attention, and inventive power, are re- 
quisite to conceive and follow out the idea of their em- 
ployment in this manner. 

The inconveniences of raw hides, and their roughness 
and hardness preventing their adaptation to the body, 
awoke reflection ; men thought to discover the causes of 
these defects, as well as the means of remedying them, 

* From the "Gerber Courier," Vienna, Austria. 



32 INTRODUCTION. 

and thus arose with a gradual progress towards perfection 
the art of converting the raw hide into leather and for 
clothing, which mode of preparation is now called Tan- 
ning. 

The more nations increased in number, the greater 
became the demand for the necessity of civilization and 
luxury, and thus forced and attracted by necessity and 
gain, many experiments were made with a view to the 
improvement of tanning, until those excellent inventions 
were attained which have brought tanning to its present 
state of perfection. In these experiments the principal 
properties of tanned leather were not lost sight of. At- 
tention was paid to the preparation of the hide so as to 
render it pliant and more impervious to moisture. 

New inventions and discoveries are still making 
every day by workmen and scientific men ; often acci- 
dentally, but often by study and reflection ; and who 
knows but that in a few years tanning will be brought to 
a much higher point of perfection than it has hitherto 
attained. Chemistry, the fundamental science of tanning, 
has made astonishing progress in the last few years, and 
ought this not also to ht the case in the tanning art, es- 
pecially as it is based upon chemical principles? 

The oldest method of tanning is red, or bark tanning, 
or that in which, in addition to the wooden and iron 
scraping and rubbing instrument used in the preparation 
or improvement of the hide or skin, lime-water, and as- 
tringent extracts from oak and other kinds of bark, or 
from other vegetable substances are employed. It is 
called red tanning because the tanning substances always 
contain more or less coloring matter, which dye the 
leather through and through of a more or less reddish 
color. 

The ancient orientals understood the art of preparing 



INTRODUCTION. 33 

not only common leather, but even good, and often finely 
colored varieties, similar to our Morocco and Cordovan. 
Persian and Babylonian leather has been celebrated time 
out of mind. Many centuries back, such leather was 
brought from Asia into Europe, first into Turkey, Prussia, 
and Hungary, and thence later to Germany, Holland, 
England, France, Spain, etc., and these countries learned 
subsequently to manufacture leather themselves. In 
the first centuries of Christianity, the Turks, Russians, 
and Hungarians were the most celebrated tanners ; sub- 
sequently England, the Netherlands, and Spain endea- 
vored to equal them. 

Among fine sorts of leather of foreign origin. Cordovan, 
Morocco, Shagrin, and Russia leather have at all times 
been especially famous. Cordovan, a soft, small-grained, 
colored leather, had already been prepared by the ancient 
orientals. Its name is derived from the Spanish city of 
Cordova, where it was probably first introduced into 
Europe, and where, for a long time afterwards, it was 
chiefly manufactured. It enjoyed a great reputation in 
the eleventh century, when the most distinguished persons 
wore shoes of Cordovan leather. The French name for 
shoemaker, " Cordonnier,''' appears also to be derived 
from this leather. The best qualities are now made in 
Constantinople, Smyrna, and Aleppo. The best known 
German Cordovan is the Bremen variety. 

From the gradual improvement of Cordovan sprang 
Morocco, called also Turkish and Spanish leather, a still 
handsomer leather than Cordovan. This beautifully 
colored and brilliant leather has always been most 
excellently manufactured in Morocco, in the Levant, in 
Asiatic and European Turkey, in Krim Tartary, in 
Aleppo and Smyrna, and in the Island of Cyprus, and 
very well also in Pvussia, Poland, Hungary, and Spain, 
3 



84 INTRODUCTION. 

but especially in England, France, Holland, Switzerland, 
and Germany (in the latter country at Offenbach on the 
Main, and Calin in Wurtemburg) . 

Shagrin (in Turkish, Sagri, and Persian, Sagre) is 
chiefly celebrated for its hardness and strength, and for 
the peculiarity of the grain side, which appears as if co- 
vered with globular granules ; it is also of eastern 
origin. The best Shagrin is now made in Persia, Con- 
stantinople, Algiers, and Tripoli. The production of the 
small globular granules on the grain side was for a long 
time kept secret. We were first informed years since 
by the celebrated traveller, Pallas, that they were pro- 
duced by stamping the hard seeds of the loild orach (Che- 
NOPODIUM album) into the hide, spread on the ground ; 
the seeds were afterwards knocked out and the hide 
scraped on the indented side, and soaked in water for 
two days. There is another description of shagrin 
totally different, made from fish-skin, called fish-shin 
shagrin ; it is used for covers, wood polishing, etc. 

Russia leather is a strong and pliant leather, generally 
red or black, with a peculiarly penetrating odor, and was 
undoubtedly invented by the ancient Bulgarians. It is 
only lately that we have learned the mode of preparing 
this leather. Among other things, we first perceived 
that the peculiar odor arose from the birch oil which 
was rubbed into the leather. Inuften, the German name 
of this leather, is derived from the Bulgarian word 
^^Jufti" a pair, as the Bulgfarians, when they colored 
hides, always sewed them together by pairs in the form 
of a bag, with the grain side inwards ; the coloring liquor 
was then poured in and the hides kept in motion. The 
best Russian leather is made in various Russian and 
Lithuanian provinces. 

By tanning (i. e., white tanning), which appears to 



INTRODUCTION. 35 

have been invented in Hungary before the twelfth centurv, 
a white pliant leather is obtained by tanning with alum 
instead of bark. This leather is used principally by 
glovers and harness makers. In Hungary, also, not 
long after the invention of tanning, chamois dressing 
was invented. In this method neither bark nor alum 
is employed ; the leather is simply dressed by rollincr 
and other powerful operations, first with bran and sub- 
sequently with animal fat (train oil). In order that the 
fat may the better penetrate through and through, the 
grain side is cut away with sharp instruments. For 
this reason chamois leather is rough or velvety on both 
sides. Lately gloves and breeches are made from this 
kind of leather, the latter principally from white tanned 
buckskin. The Hungarians were, in ancient times, 
especially celebrated for their white tanned leather, 
which was imitated in France as long ago as three hun- 
dred years. In chamois leather, the most famous is the 
fine, white, shining French and Dane's leather (made 
from lamb and goat skins), from which, by means of a 
peculiar varnish, the so-called kid gloves are made. 

A profession continues progressive, and cannot reach 
its highest point until its limits can be precisely defined. 
An excellent means by which to improve a profession, 
consists in pointing out the goal and end to be attained, 
and the bounds within which it must be confined. With- 
out this precaution, we exhaust ourselves in single and 
unconnected researches, without reference to each other, 
and the knowledge which we acquire is dissipated and 
loses in force as it recedes from the common focus. 

A small number of principles and a great mass of con- 
clusions ; this is the history of all arts, all sciences. 
The principles must rest upon reliable facts derived from 
experience and observation ; but an author cannot render 



36 INTRODUCTION. 

all conclusions and explanations. The principles are 
not numerous^ and are easy of comprehension, but the 
conclusions arising from them are innumerable, and 
lucidity is only to be arrived at by placing them in order 
under the general laws to which they respectively belong, 
and, therefore, a judicious classification is requisite. 

Tanning, in general, is divided into various branches, 
although all may be practised together by the same tan- 
ner. We will first give nearer data upon the origin and 
development of our system of tanning, and subsequently 
consider minutely and singly every process and the 
different methods and systems in our* tanneries at home 
and abroad, keeping constantly in view the statistics of 
the foreign leather trade and manufactures as compared 
with our own. We beg our readers to go back some 
centuries in history, and they will be convinced that 
the products of our trade were known in the time of 
Moses ; for at that period, leather carpets were already 
used in tents ; these we may still meet with at present 
among the Arabs. Colored leather seems, also, to have 
been common, for Ezekiel speaks of fine red leather 
which was probably our splendid red morocco. Leather 
was also used in the remotest ages by the Israelites as 
a material to write upon, for they used strips made of 
leather for this purpose. According to the testimony of 
Herodotus, the ancient lonians wrote their annals upon 
sheepskin, and the ancient Persians, likewise, according 
to Diodorus of Sicily. 

According to the accounts of Herodotus, the ancient 
Libyans wore leather clothing; the Ichthyophagists on 
the banks of the Araxes dressed themselves in sealskins, 
and in the time of Alexander, the wild inhabitants of 
Geodrosia used the hides of animals for clothing and 
covered their dwellings with leather. 



INTRODUCTION. 37 

Homer praises the splendid half boots of Agamemnon, 
and Hesiod recommends leather shoes lined with fur. 
For many years leather was used by the Greeks in the 
construction of ships; especially by the Phoeniciansk, who 
originally inhabited an arid sandy corner of the earth, 
between the Red Sea and the Mediterranean, where the 
soil was not favorable to the growth of timber, and they 
were obliged to supply its place by covering their boats, 
constructed of willows woven together, with leather or 
hides, which even thus early were subjected to a certain 
amount of dressing. The ancient Germans, also, who 
lived on the sea-coast, and the original Britons equally 
possessed this custom. 

It is asserted that the art of dressing leather in general 
upon the so-called Hungarian method, was first brought 
from Senegal, in Africa, and made kno"wn to us in the 
middle of the sixteenth century, by one Buscher, the son 
of a tanner in Paris ; at that time leather was common 
in Hungary, and that dressed there was very highly 
esteemed. In the year 1584, two German tanners 
named Lasmagne and Aarand came to Neuchatel in 
Lorraine, where they worked at their trade ; from thence 
they went to St. Diziers, in Champagne, and finally to 
Paris, w^here they prepared very good leather. 

The theory that the preparation or tanning of hides 
was discovered centuries ago, and that the leather pro- 
duced was employed for the same purpose as at present, 
is further confirmed by the following old proverb, which 
is a proof that leather shoes were already worn at that 
time, viz : " We must not steal leather to give away shoes 
in GocVs name!' This refers to the legend of St. Crispin, 
who stole leather to make shoes out of it for the poor. 
In the old form of speech, " To draiv from, the leather" 



38 . INTRODUCTION. 

signified to draw the sword. In low Saxon the same 
expression signifies to undress. / 

Parchment Dressing. — Parchment was known long 
befor# the invention of paper ; for sheep and goatskins 
were used to write upon in the time of Herodotus, 484 
A. C. ; the name is derived from the City of Pergamus, 
in Asia Minor, where it was excellently manufactured. 
The best parchment is prepared fromi calfskin, and 
inferior qualities from sheep, goat, ass, and pig skins. 
The fine virgin parchment is made from the skins of new- 
born lambs. 

Artificial parchment, which was discovered in Eng- 
land, consists of linen, cloth, or paper, which is tightly 
stretched, and then a paste composed of gypsum, white 
lead, powdered lime, water, and parchment glue, is laid 

on with a brush four times : it is then smoothed with 

» 

pumice stone, and lastly steeped in a bright oil varnish. 

The use of parchment is not very extensive ; beyond 
the ordinary purposes it is sometimes used for printing, 
for organ bellows, and for sieves, and in England for 
sounding boards in stringed musical instruments. In 
Germany it is principally manufactured at Bentheim 
and Schuttorf in Hanover, and also in Augsburg, Nu- 
remberg, Breslau, and Dantzic. Holland, England, and 
France manufacture excellent parchment. 

Such is the historical origin of our leather trade. 
The gradual development ^nd progress of technical tan- 
ning have been promoted and assisted by many, and 
among the most zealous are MacBride, St. Real, Prouf>t, 
Hermstadt, Vauquelin, Cliaptal, Seguin, Desmond, Von 
Meidinger, Aikin, and others. Attempts have been made 
to discover new methods by which hides and skins 
could be better tanned, and in a shorter space of time, 
than by the usual mode of treatment. In the year 1778 



INTRODUCTION. 39 

MacBride discovered the process of raising with diluted 
sulphuric acid (1 part acid to 400 parts water). 

Later great attention was attracted to the system of 
quick tanning, discovered in 1795 by Seguin, by which 
hides and skins were tanned in much less time than 
formerly. This new process was tested by experts, and 
found to be partially good and partially deficient. In 
1801, Banks discovered the tanning property of Terra 
Jajponica (Catechu). Since that time tannin has been 
discovered in a great number of plants. 

The English discovered, in the last century, the art 
of varnishing leather, which was soon after imitated in 
Germany with complete success. 

Bellamy, Von Hildebrandt, Edward, and others in- 
troduced the art of preparing water-proof leather. 

Whatever may be facts, it is to be presumed that the 
most ignorant races of antiquity, whose chief occupation 
was the chase, possessed the knowledge of giving a cer- 
tain preparation to the raw animal hides to protect them 
from decay, and to render their necessary clothing con- 
venient; they were certainly driven to invention by 
necessity, and thus the invention of the art of tanning 
was probably the work of accident, like the invention 
of most of the other arts. To them, consequently, must 
the invention of the art of tanning leather be ascribed, 
although it must be conceded that this art owes its 
proper cultivation and perfection to more recent ages. 



PART I. 

CHEMISTEY OF TANNING. 



SECTION I. 

TAN AND TANNIN. 

The second principal component of leather, such as 
that manufactured into boots, shoes, &c., is Tannin, or 
tannic acid, a substance of vegetable origin and very ex- 
tensively disseminated in plants and trees. For a long 
time the agents which gave such virtues to oak bark, 
in converting prepared skins into leather, were little 
known, and, consequently, the peculiar relation of the 
proximate principle of this article could not be under- 
stood, notwithstanding that, in the absence of this know- 
ledge, the leather manufactured was sometimes of prime 
quality. Dr. Lewis was the first who drew the attention 
scientifically to the subject. He observed, during an 
investigation of the nutgalls, that they contained a sub- 
stance which gave a black compound with a sesqui-salt of 
iron and precipitated isinglass. Deyeusee, who also 
studied the subject, noticed this substance, but considered 
it a peculiar resinous matter. It was not, however, till 
Seguin published the results of his labors, that any defi- 
nite account of it was given. This chemist showed that 
the unknown body differed from the acid of galls — gallic 
acid; that it combined with animal matters, more particu- 



42 CHEMISTRY OF TANNING. 

larly albumen and gelatin, and formed with, them unal- 
terable bodies, the analogue of which constituted the main 
bulk of leather. Since then, manufacturers have given 
great attention to this principle in the tanning material, 
and the consequences are that a greater variety of sub- 
stances producing tannin, or desirable for making leather, 
have been discovered, and that considerable expedition 
in the process has been attained. Although the before- 
mentioned chemists, with Davy, Chevreul, Pelletier, 
Lagrange, Guillot, Hatchett, Tromsdoeff, Richter 
and Proust may be justly said to have given a scientific 
exposition of tannic acid and its behavior, and likewise 
pointed out its quantity in those plants that yield it most 
abundantly, still several more recent investigations have 
contributed to the stock of information on this subject. 
According to Wahnlenberg, tannin exists only in pe- 
rennial plants and almost solely in the permanent parts. 
For example : — 

1. In the perennial roots of certain annual plants, as 
the Sepffoil and Bistort or snakeweed. 

2. In the bark of the trunks and roots of nearly all 
perennial trees, especially in the true cortical portion. 

' 3. In the trunk and sap of many trees. 

4. In the leaves of perennial plants. 

5. In the leaves of different varieties of oak, of the 
Rhus coriara (Sumac), of the Ai-hutus uva ursi (Bear- 
berry), of the Arbutus unedo (Strawberry), etc., in 
large proportion. 

6. In the capsule of the unripe fruit of the Quercus 
suber (Bgilops (YaloniA oak), Juglans regia (Walnut); 
JEsculus hippocastanus (Horse-chestnut). 

7. In the pulp of the fruit of the Panica grayiatum 
(Pomegranate) ; Rosa jpimpinelU foHa ; Garcinia man- 
gostana (Mangosteen), and in dijfferent species of Anona. 



TAN AND TANNIN. 



43 



The following table exhibits the names of the principal 
materials used by tanners. 



Common Name. 


Botanical Name. 


Groiuth. 


Oak bark 


Quercus pedimculata 


Every country. 


Larch " 


Pinus larice 


Scotland. 


Mimosa " 


Acacia sp. 


New South Wales. 


Baboul " 


Acacia arahica 


Bengal. 


Cork Tree " 


Quercus suher 


Laruch, Rabat, etc. 


HExMLOCK " 


Abies canadensis 


United States. 


Sumach " 


Rhus coriaria 


Sicily. 


Yalonia 


Quercus cegilops 


Smyrna, Trieste, etc. 


Divi-Divi 


Ccesalpinia coriaria 


Maracaibo, Rio de la 
Hacha, Savanilla. 


Myrobalans 


Terminalia sp. 


Bengal. 


Algarobilla 


Prosopis pallida 


Valparaiso. 


Terra Japonica 


Acacia catechu 


East Indies. 


CUTCH 


11 li 


Calcutta, Singapore. 


Kassu ' 


Areca catechu 


Ceylon. 



Besides the foregoing, which are partly well known in 
the trade, other astringent substances have been brought 
before the public to be employed per se, as tanning 
materials, or with oak bark as an adjunct. These are 
various extracts from species of the acacia tribe; Gam- 
BiR, the extract of the Nauclea gamhir from Singapore ; 
Maitrove bark [Rhizopora mangle), from Arracarice; 
TuRWAR or Cassia bark ; Avaraputtai ( Cassia a.uricu- 
lata), from Vazigapatam ; Saracondraputtai ( Cassia fis- 
tula), from Madeira; Saul tree bark from the S<iul For- 
ests; Pomegranate rind ; Darunkapucke [Dahimajegota), 
from Kemaon ; Dalumka Khola from Calcutta ; Jamoon 
bark [Eugenia jamholana) ; Pearl bark from Cuttah ; 
Samah bark from Singapore; Yangat or Gum kino, 
{'pterocarpus dalhergoides) , from Malabar; KiNO extract 
of the Buchdnania patifolia, etc. etc.. 



44 CHEMISTRY OF TANNING. 

We must note here — 

1. That tannin is never found to any extent in the 
interior of the trunks of trees. 

2. That it does not exist in poisonous plants, nor in 
those with a milky or viscid sap. 

3. That its proportion is greater in old than in young 
plants. 

4. That the tannin is converted into bitter principle, 
as the plant increases in age. 

5. That it is most abundant in the cortical layers of the 
bark, and is usually absent altogether in the epidermis. 

6. That the proportion of tannin in bark varies with 
the season, decreasing as the severity of the winter in- 
creases. 

7. That the true extreme in quantities are allowed 
in winter and spring. 



CHAPTER I. 

PURE TANNIN. 

CHEMICAL PROPERTIES OP PURE TANNIN — COMPOSITION — PREPARATION. 

Chemical Properties. 

By examining any of the numerous substances men- 
tioned above, it will be found that they yield a product 
which is capable of precipitating a solution of gelatine, 
and also of giving a greenish or bluish-black one, with 
solutions of sesqui-salts of iron. To matter exhibiting 
this reaction, and having an astringent taste, the name 
of Tannin was given, irrespective of whatever difference 
might be exhibited upon further comparison. Now many 
of those bodies which, in common with the true type of 



PURE TANNIN. 45 

tannin (that which is extracted from galls), precipitate 
gelatin, and so far show that they are eligible for 
tanning materials, are known to differ in that character- 
istic ; for instance, some possess acid properties, whilst 
others are devoid of them ; and although towards gela- 
tin, their reactions are similar, their atomic constitu- 
tion is widely different. Kegarding their effect in con- 
verting skin into leather, this dissimilarity is not very 
material, as, when the components of each one are com- 
pared, a distinction is also made with respect to the 
physical appearance of the precipitate they afford with a 
sesqui-salt of iron, and by this all the known tanning 
materials are divided into two classes.' In the first of 
these are placed gall-nuts, and the barks of the several 
oaks, and the second include the quinquina, the cachou, 
kino, pine barks, etc. The tannin afforded by the first 
throws down a bluish-black or purple combination, whilst 
the precipitate afforded by the second is greenish. Ex- 
periments have shown that such distinctions are not very- 
marked, since the tannic acid from nutgalls or oak bark, 
in the presence of an alkali, will occasion a greenish pre- 
cipitate when added to a sesqui-salt of iron, and a bluish 
or violet compound when acid's are present. 

Hatchett first observed that many plants contain a 
carbonaceous principle, which, when acted upon by ni- 
tric or sulphuric acids, according to the method of Chev- 
REUL, yield a substance which, like the tannin of the 
foregoing barks and fruits, throws down gelatin, and 
renders it imputrescible. This variety has been desig- 
nated artificial tannin ; but in the present state of chem- 
ical science, it could not be compounded with the na- 
tural products. Beezelius, Geiger, Waltl, and Caval- 
Lius are of opinion that tannin, from whatever source it 
may be obtained, is identical,and that the difference of the 



46 CHEMISTRY OF TANNING. 

reaction with the iron salt must be attributed to im- 
purities which are accidentally present. Stenhouse, in 
his more recent researches, has shown that such is not 
the case, but that all those forming precipitate with ses- 
quioxide of iron, varying from the color of that which 
the tannin of nutgalls affords, must be regarded as a dis- 
tinct substance, in which case there seems to be an almost 
endless variety. Even when the iron reactions of some 
tannins agree, and also appear analogous in other chem- 
ical relations, the same chemist states that the compo- 
sition is frequently diverse. 

In its purity tannic acid is colorless, inodorous, pos- 
sesses a highly astringent taste, and is very soluble in 
water. It is, however, devoid of all bitterness, notwith- 
standing its astringency is so powerful. On testing the 
aqueous solution with litmus, the reaction evidences the 
acid nature of the tannin ; and further, by treatment with 
an alkaline carbonate, carbonic acid is freely displaced, 
showing that a combination of the alkaline base and the 
tannin has taken place. With the oxides of the heavy 
metals it in a great measure combines, giving rise to 
precipitates which are the tannates of the respective bases, 
and generally possess a color more or less remarkable. 
Thus an infusion of nutgalls reacts in the following 
manner : — 

With a neutral solution of salts of 





Precipitates given. 




Brande. Dumas 


Protoxide op Manganese, 


Dirty yellow, — 


" Ikon, 


Purple tint, — 


Sesquioxide of Iron, 


Black, Blue hlack. 


Oxide of Zinc, 


Dirty yellow, — 


Tin, 


Straw " Yellowish. 


BlOXIDE " 


Fawn " 


Oxide op Cadmium, 


— — 





PURE 


TANNIN". 




^ 






' 


Precipitates given. 




Brande. 


Dumas. 


Protochloride of Copper, 


Yellow hrown, 


Gray. 


Protonitrate, " 


Green, 




It 


Oxide 


OF Lead, 


Dingy yellow, 


White. 


Teroxide op Antimony, 


Straw 


<< 


11 


<( 


Bismuth, 


Yellow, 




Orange. 


Oxide 


OF Cobalt, 


— 




Yellowish-white. 


Salts 


OP Cerium, 


— 




Yelloioish. 




Titanium, 


— 




Blood color. 




Tellurium, 


— 




Isahelle yellow. 




Chromium, 


— 




Brown. 




Tantalum, 


— 




Orange. 




Molybdenum, 


— s 




Brown. 




Uranium, 


— 




Brownish-red. 




Silver, 


— 




Pale yellow. 




Platinum, 


— ■ 




Greenish shade. 




Gold, 


— 




Brown. 




Osmium, 


— 




Bluish-purple. 



47 



In making the foregoing experiments, it is necessary 
to employ neutral solutions of the. salts, otherwise any 
excess of the acid may not only alter the shade of the 
precipitate but prevent it altogether. This is especially 
the case with salts of iron and titanium. When a solu- 
tion of tannic acid is added to another of protosulphate 
of iron, according to Mr. Dumas, no precipitate occurs; 
but if one of the sesquisulphates be substituted there is 
an abundant deposit of a blue-black color. 

By exposing a solution of tannic acid to the air, at a 
moderately elevated degree of heat, oxygen is freely 
absorbed, and an equal volume of carbonic acid is disen- 
gaged. Upon examination, the matter in solution- will 
be found to be wholly transformed into two other sub- 
stances, gallic and ellagic acid, the former of which is in 
excess, and is dissolved in the liquid, whilst the latter 
remains insoluble in the form of a yellowish powder. 



48 CHEMISTRY OF TANNING. 

This transformation takes place in the aqueous extract 
of gall-nuts, much more readily than in one of pure tan- 
nin ; this is particularly the case if the marc or insoluble 
residue of the galls be left in contact with the liquid, as 
it induces a fermentative action, which brings about the 
transformation the more readily. When boiled with hy- 
drochloric or sulphuric acids, gallic acid is also formed, 
together with grape sugar, which, as Strecker states, re- 
mains in the mother liquid after the newly-formed acid is 
removed by crystallization. The change here induced 
may be represented thus : — 

C54H3203* + lOHO = ^(Ci*H3073HO) + G'^W^0'''2A(i. 

Gallo-tannic acid. Water. Gallic acid. Cellulose. 

A concentrated solution of caustic potash at the boil- 
ing point, has also the effect of transforming tannic into 
gallic acid ; and if air or oxygen be admitted, of con- 
averting the latter into an ulmin-like substance. Hydro- 
chloric, nitric, phosphoric, and arsenic acids occasion in 
strong solution of tannic acid white precipitates which 
are, as stated by Berzelius, compounds of the tannin 
with those acids ; all these precipitates are, however, read- 
ily decomposed, and their tannin changed into gallic acid, 
beseizing them with dilute sulphuric acid, or with an ex- 
cess of alkali. If a cold aqueous solution of tannin be 
mixed with another of gelatin, isinglass, bone-size or 
glue in excess, an opaque white precipitate is obtained 
of tanno-gelatin, that is soluble in the supernatant fluid 
by the help of heat. When, however, the conditions 
are reversed, and an excess of tannin is taken, it happens 
that, instead of dissolving, the precipitate agglutinates, 
and forms a membranous matter of a grayish hue, that 
possesses considerable elasticity, and thus approaches 
caoutchouc. The solutions filtered from these bodies 



PURE TANNIN. 49 

strongly tinges those of the sesqui-salts of iron. It ap- 
pears that tannin solutions react in a similar way with 
protein compounds in general. 

It was thought for a long time that the insolubility of 
the tanno-gelatin offered a means for insuring the purity 
of tannin, and of detecting the absence or presence of gal- 
lic acid in the sources affording tannin ; but this insolu- 
bility, excepting in water alone, does not answer the pur- 
pose. Pelouze employed a piece of skin, cleaned in 
the ordinary way from hair and epidermis; this was im- 
mersed for some hours in the extract, and the whole agi- 
tated occasionally, and finally the liquid filtered. When 
pure tannin was operated upon, the whole combined with 
the integument, so that the fluid has no astringent taste, 
nor did it color a solution of a sesqui-salt of iron, but if 
gallic acid had been mixed with it, the bluish-black tint 
would present itself in the latter case. 

Freshly precipitated alumina, agitated with a solution 
of tannin, absorbs the latter rapidly and forms with it 
an insoluble compound ; gallic acid behaves in a similar 
manner. At the temperature of an oil bath, tannic acid is 
decomposed, water and carbonic acid being formed ; but 
when the heat is increased, other products are generated, 
and nothing remains but charcoal, which, if heated on 
platinum wire, burns, leaving no residue. Strong ether 
dissolves tannin, and forms a syrupy liquid, which does 
not combine with fresh ether. Alcohol behaves with 
tannin in the same way, the solvent power of the spirit 
decreasing in reference to it as it approaches purity or 
dehydration. 



50 CHEMISTRY OF TANNING. 

Composition. 

According to Berzelius, tannin such as it was prepared, 
i. e., impure, was composed of 

Oarhon 52.69 

Hydrogen . . . . . .3.86 

Oxygen ....... 43.45 

100.00 

Pure tannin, according to Pelouze, is thus formed : — 

Garbon ....... 51.40 

Hydrogen ...... 3.51 

Oxygen . . . ... . .45.09 

100.00 
These numbers nearly correspond with the formulae 
(;;i8jj8Qi2^Qi8H5 Q^SHO. But Strecker, in his later re- 
searches, gives the equation thus, C^*H^^O^^, showing 
that it contains less oxygen and hydrogen than is indi- 
cated above. 

Preparation. 

When tannin is to be obtained in its greatest state of 
purity, recourse must be had to the process known as 
that of Pelouze, but which was first broached by Lambert. 
The latter chemist directed the formation of an extract 
of 60 grains of powdered nutgalls in 120 grains of ether, 
the digestion to be continued for twenty-four hours, after 
which the ethereal extract was to be filtered and evap- 
orated. Pelouze followed the foregoing method in prin- 
ciple by employing the apparatus of Robiquet and Bou- 
tron as used for the preparation of Amygdalin. Fig. 1 
represents this digester. It is an elongated glass vessel 
A, having an orifice at the top, which is fitted with a 
ground glass stopper, and contracting towards the other 
extremity, which fits tightly into the neck of a bottle 



PURE TANNIN. 



51 



or matrass B which receives the ex- ^^s- ^• 

tract. Sometimes the lower bottle 
has a second tubular opening, D, 
for the purpose of receiving a cork 
furnished with a tube, to which a 
connector, G, of caoutchouc is ap- 
pended, the other end being attached 
to a similar tube fitted in cork which 
closes the top orifice. Between F G 
is the powdered gall, and in jE/ is a 
little batting cotton. This adapta- 
tion causes the filtration to take 
place more readily, whilst it pre- 
vents contact with any further quan- 
tity of air beyond what is contained 
in the apparatus. Common sulphuric 
ether is then poured upon the galls, 
and as it traverses the powder it 
takes up the tannin and gallic acid. 
The latter, however, gives a lighter 
and more fluid solution than tannin, and forms the 
upper stratum of the ethereal solution which has tra- 
versed the galls and dropped into the receiving bottle. 
The dense and dark-colored stratum below contains 
tannin. The galls are treated successively with new 
quantities of ether until they cease to yield soluble mat- 
ter. The several ethereal solutions are then mixed 
together and poured irito a separating funnel. When 
the two strata have formed, the lower one containing 
the tannin is drawn off into a retort, distilled to sa.ve 
ether, then repeatedly washed with pure sulphuric ether 
to remove traces of gallic acid, and evaporated over a 
warm sand-bath or under the receiver of an air pump ; 
the tannin is obtained in the form of a spongy, iridescent, 




52 CHEMISTRY OF TANNING. 

uncrystallizable mass having a light shade yellow color. 
So prepared, tannin is in its purest known state ; but as 
sometimes it results almost colorless, doubtless it is not 
free from impregnation arising from decomposed tannin, 
apothema, or some other matters. 

Another modification of the method just detailed was 
introduced by Domine, and offers the advantage of yield- 
ing a larger product, while it admits also of being applied 
on the large scale for the purpose of the manufacturer. 
He places the powdered galls in a damp cellar for several 
days, during which they absorb moisture; the powder 
is next transferred to a wide-mouthed jar, and made 
into a paste with ether of a specific gravity 0.75. After 
this the vessel is hermetically closed, and the contents 
allowed to digest for 24 hours. At the expiration of 
this time the pasty contents are transferred to a strong 
linen bag and subjected to gradual pressure, when the 
ethereal extract of tannin, having a dark syrupy con- 
sistence, flows off into the receiver. This liquid must 
be evaporated to dryness at a gentle heat, by which the 
tannic acid is left in the form of light-colored resin-like 
scales. The compressed residue is further treated with 
ether, to which six per cent, of water is added in the 
same manner as when preparing the first extract, and 
on expelling the fluid by a gentle heat, a residue of tan- 
nin is obtained. It is, indeed, more impure than the 
above, as it contains chlorophylle, volatile oil, and gallic 
acid ; still the tannin thus prepared answers very well 
for many industrial purposes. 



IMPURE TANNIN. 53 



CHAPTER II. 

TMPUEE TANNIN. 

CHEMICAL PROPERTIES OP IMPURE TANNIN — PREPARATION — VARIETIES 
IN THE IMPURE TANNIN. 

Impure tannin is solid, brown, transparent, friable, 
uncrystallizable, odorless, has a very astringent taste; it 
is heavier than water, reddens the solution of litmus, 
softens in the fingers, melts at a low temperature; it is 
very soluble in water, principally while warm; by cooling 
it precipitates a light yellowish powder. The solution 
has a brown color, and is not decomposed when exposed 
to the air even at a middling temperature. Little solu- 
ble in absolute alcohol, it dissolves in it only by the 
addition of a little water in the proportion of 0.10. 
According to the experiments of Proust, Deyeux, and 
Davy, it combines with oxygen, but then it is decom- 
posed or altered in its nature. According to Bouillon- 
Lagrange, it is transformed by this absorption into gallic 
acid. It precipitates albumen and gelatine from their 
dissolutions and forms insoluble combinations. 

Hydrochloric and sulphuric acids precipitate the aque- 
ous solution of impure tannin; the precipitate, which is 
very slightly soluble in cold water, but very soluble in 
hot water and alcohol, is a combination of tannin with 
the acid employed. 

Acetic, arsenic, malic, oxalic, and tartaric acids pre- 
cipitate the infusion of nutgalls; this precipitate, washed 
with cold water and dissolved in boiling water, has all 
the properties of the tannin. Nitric acid and chlorine 



54 CHEMISTRY OF TANNING. 

destroy it easily ; the first transforms it into a brown 
yellowish substance, soluble in alcohol and similar in its 
properties to an extract. According to Proust, it is the 
same for the stannic acid. Pure and carbonated alkalies 
form with this substance combinations nearly insoluble. 
Metals have not a sensible action on impure tannin, but 
the greatest number of oxides combine with it and ren- 
der it insoluble in water. 

Baryta and lime-waters decolorize the solution of im- 
pure tannin and produce a precipitate which is a combi- 
nation of tannin with the oxide; this precipitate is 
nearly insoluble in water and without action on gelatine ; 
it differs from the combination of this last substance with 
the tannin in which they cannot be separated, because 
they form a new compound. In the combination of the 
tannin with an alkali or earth it can be isolated by treat- 
ing the combination by an acid which dissolves the 
oxide and sets free the tannin. 

By agitating recently precipitated magnesia or alumina 
in a solution of tannin, it forms a tannate of magnesia 
and alumina, insoluble in water and decomposable by 
acids which render the tannin soluble in that liquid. 
If we treat the infusion of nutgalls by baryta, strontia, or 
lime-waters, the precipitate has an olive color, and is com- 
posed of tannate and gallate united with the extractive. 

If we boil magnesia with an infusion of nutgalls, the 
precipitate has a dirty yellow color, insoluble, composed 
of tannin, extractive, and magnesia, while the gallate 
of magnesia stays dissolved in the liquor. 

Alumina in small proportions gives the same results ; 
in large quantities it separates all the substances which 
constitute the infusion. The alkaline carbonates sepa- 
rate from the gallic infusion the tannin and extractive ; 
the formed gallate stays in solution ; the solution of tan- 



IMPURE TANNIN. 55 

nin does not decompose salts of the first section, but on 
the contrary it operates the decomposition of many 
belonging to the four last. 

In solution of copper it produces an olive precipitate. 

In sulphate of manganese it produces a fine light green 
precipitate. 

In nitrate of mercury the precipitate is light yellow. 

In that of titanium it is blood red. 

In binoxide of iron it is bluish. 

In teroxide of iron it is gray black. 

Tannin unites and forms combinations nearly insoluble 
with some other principles, such as starch, gluten, ligne- 
ous fibre, albumen, casein, mucus, etc. Tannin submitted 
to the action of heat swells and is decomposed ; by dis- 
tillation it gives a black liquor which precipitates black 
the dissolutions of iron. This precipitation is due to a 
little pyrogallic acid. The residue in the retort is a very 
voluminous charcoal which amounts to the 0.0263 of the 
decomposed tannin. 

Preparation of Tannin from Nutgalls. 

In the art of tanning, the decoction used contains, 
besides tannin, gallic acid, extractive, and other soluble 
vegetable principles. Different processes have been pro- 
posed to isolate it; they do not produce it pure, but in 
a state sufficiently so for many purposes. 

Prousfs Process. 
This chemist advises exhaustion of the nutgalls by 
water, and to pour into the liquor a dissolution of hydro- 
chlorate of tin till it does not precipitate. Proust called 
this precipitate tannate of tin ; it is yellowish-white. 
When washed and diluted in cold water he passes through 
it a current of hydrosulphuric acid gas, filters, and evapo- 



56 CHEMISTRY OF TANNING. 

rates to dryness. According to this chemist it is pure 
tannin, but it has been ascertained that it contains a 
little gallic and hydrochloric acids and extractive matter. 

Deyeuxs Process. 

He makes a strong infusion of nutgalls and precipitates 
it with a concentrated solution of carbonate of potash. 
He obtains an abundant precipitate, yellowish-white, 
which by drying forms a whitish powder. This product 
is far from being pure. Davy and Tromsdorff have 
ascertained it was a combination of tannin, gallic acid, 
carbonate of potash, and lime. * • 

Dizes Process. 

This chemist has ascertained that by pouring concen- 
trated sulphuric or hydrochloric acid into a concentrated 
infusion of nutgalls, a white precipitate was obtained. 
Proust considers it like a combination of tannin with 
the acid employed. To purify it, it is sufficient to wash 
it with cold water, dissolve it in warm water, and satu- 
rate the acid by carbonate of potash. This tannin is 
not pure. Besides the extractive precipitated by sul- 
phuric acid, it contains gallic acid. 

Merat- Quillofs Process. 

He precipitates the infusion of nutgalls by lime-water, 
and treats the precipitate by diluted nitric or hydro- 
chloric acid. An effervescence is produced, and the 
liquor takes a dark color. The filtration separates a 
bright black substance that this chemist calls pure tan- 
nin, but as Davy has demonstrated it is united with 
extractive combined with the lime. 



IMPURE TANNIN. 57 

Bouillon-Lag ranges Process. 

His method consists in precipitating the infusion of 
galls, by carbonate of ammonia, washing the precipitate 
with cold water, and digesting repeatedly in fresh por- 
tions of alcohol at 0.817. This process is as defective 
as the others. 

Tromsdorff^s Process. 

He infuses, for three days, at a temperature of 65° a 
mixture of 

Powdered nutgalls ..... 3 lbs. 
Water ....... 5 gals. 

Stir often, filter, add a new quantity of water, and repeat 
the operation until the liquor does not precipitate with 
sulphate of iron. Mix all the liquors, evaporate them 
at a gentle heat, and filter through a cloth to separate 
the extractive. Evaporate anew until it has the consist- 
ence of a jelly, and dry in the oven; treat several times 
with alcohol at 0.796 till it does not contain gallic acid. 
For this purpose he treats the tannin twice by alcohol 
at 0.10. It then contains a little mucous and extractive 
matter. To separate them he dissolves the tannin in 
water and exposes it to the air. It forms a moisture 
that he separates by filtration and evaporates to dryness. 
The residue is pure tannin, containing, however, a little 
sulphate of lime; to eliminate it he dissolves it in water 
and adds carbonate of potash until no more precipitate 
is formed. He filters, and to the dissolution he adds 
acetate of lead, which forms a precipitate or combination 
of tannin with oxide of lead. He washes the precipitate, 
and when dry makes a paste with it and water, and 
decomposed with sulphuretted hydrogen gas to separate 
the oxide of lead at the state of sulphuret. He evapo- 



58 CHEMISTRY OF TANNING. 

rates the filtrate to dryness. The tannin is as pure as 
it was possible to obtain it at that time. 

Serturner's Process. 

This chemist precipitates the alcoholic infusion of nut- 
galls by warm carbonate of potash. He decants and 
washes the residue with alcohol, he dissolves in water, 
separates the carbonate of potash by sulphuric acid, 
evaporates and treats the residue with alcohol. The 
excess of sulphuric acid is precipitated by carbonate of 
lime. He filters and evaporates the filtrate to dryness. 
The residue is tannin containing very little gallic acid. 

These different processes are for giving pure tannin ; 
for the properties to be astringent, soluble in water, and 
precipitate the gelatine belong to some other substances 
of a different nature which are confounded in the 
generic name of tannin. 

Varieties of Impure Tannin. 

"We have said that notwithstanding the numerous 
works of the old chemists, they never succeeded in 
obtaining pure tannin. It was impossible for them to 
separate it from foreign substances principally from the 
extractive with which it forms a very intimate combina- 
tion, as it is to the extractive that were due the varieties 
observed in the different tannins. The less impure was 
that extracted from grape-seeds ; as that of nutgalls it 
precipitates the gelatine in blue white. 

That of sumach precipitates it yellow. 
" ^^ quinquina " " DARK ROSE. 

" " catechu " " dark-brown red. 

That of Brazil wood forms with gelatine a precipitate 
very soluble in water. 

Proust affirms that there exist several varieties of 



IMPURE TANNIN. 59 

tannin, but it is very probable that these varieties are 
combinations of tannin with the above substances. In 
many cases, tannin has much analogy with gallic acid ; 
it is nearly impossible to completely deprive it of the 
latter, at least they have the property in some circum- 
stances of being transformed, the tannin into gallic acid, 
and the gallic acid into tannin. 

The moulded infusion of nutgalls gives more gallic 
acid than a fresh infusion, by treating it with absolute 
alcohol. This example proves that the tannin can be 
transformed into gallic, and reciprocally. 

Tannin of Catechu. 

' Davy has indicated the following process for extracting 
tannin from catechu. He treats it by alcohol, evaporates 
the extract, treats the residue by water, and evaporates 
to dryness. This tannin is astringent, sweetish, soluble in 
water and alcohol ; the dissolution is of a dark-red brown. 
Potash, ammonia, magnesia, increase the color without 
precipitation. Sulphuric and hydrochloric acids precip- 
itate it pale brown. The salts of protoxide of iron are 
not precipitated by this tannin. Those of peroxide of 
iron are precipitated olive-green ; starch, gluten, ligne- 
ous fibre, gelatine, albumen, form with it an insoluble 
precipitate. 

Tannin of Bark of Trees — Sumach — Kino. 

Tannin from bark of trees is not difierent from that 
from nutgalls. The others have more or less analogy 
with those of catechu or nutgalls. 

Tannin, according to the nature of the substance from 
which it is extracted, precipitates the dissolution of iron 
in blue or green, which is an indication of a variation in 



60 CHEMISTRY OF TANNING. 

its constituents. The following table indicates the 
principal tannins which give these two precipitates. 

1. Tannin which forms a bluish-black precipitate 
IN solutions of a sesqui-salt of iron : — 

Tannin from nutgalls, 

" " the barks of oak, heech, poplar, hazel, chest- 

nut, maple, horse-chestnut, cherry, apricot, 
plum, elder, winter, and other barks. 

" " the bark of sumach. 

" " logwood. 

" " roots of Uthi'um, salicaria, iris, pseudocorus, 

geum urhanum, polygonum bistortum, al- 
chemilla vulgaris. 

" " the leaves of the arhutus uva ursi, amo- 

thera hiennis, geranium pratense, etc. 

" ' " the husks of the ccesalpina coriaria. 

" " lentils, etc. 

2. Tannin which forms a green precipitate in the 
dissolution of iron. 

Tannin from catechu [juice of the Mimosa catechu). 
" " hino (juice of the Coccoloba uvifera) . 

" " cinchona harks. 

" " the roots of the rumex aquaticus, tormentilla 

erecta, polypodium Jilix mas. 
" " the tea and hadiane. 



ARTIFICIAL TANNIN. 61 



CHAPTER III. 

ARTIFICIAL TANNIN. 

PROPERTIES — COMPOSITION — PIRST VARIETY — SECOND VARIETY — THIRD 
VARIETY — PREPARATION OP AN ARTIFICIAL TANNIN PROM TURF. 

Properties. 

Besides the foregoing, chemists distinguish oth^r va- 
rieties of tannin, which result from, the chemical action 
of several powerful agents upon many substances ; as, 
for instance, from the action of nitric acid upon charcoal 
and indigo, and likewise from the effects of sulphuric 
acid upon resin and camphor. The first notice of arti- 
ficial tannin was published by Hatchett in the Transac- 
tions of the Royal Society in 1801 ; he discovered it whilst 
making experiments upon the slow carbonization of 
plants. This tannin is different, however, from other 
varieties of this substance at present known. 

Artificial tannin is a brown inodorous substance, hav- 
ing a vitreous fracture, and very soluble in water. 
Thomson states that alcohol of sp. gr. 0.80 dissolves it, 
and so far it manifests a difference of behavior from 
natural tannin. The aqueous solution of this substance 
precipitates gelatine of a brown color, but the shade 
deepens as the liquids are more dense. This precipitate 
is a compound of tannin and gelatine, in the proportion 
of 36 parts of the former to 64 of the latter. It is in- 
soluble both in hot and cold water. With the alkaline 
bases it combines, forming more highly colored solutions, 
which in the course of time get cloudy. The ammoni- 
acal solution of artificial tannin on being evaporated to 



62 CHEMISTRY OF TANNING. 

dryness and redissolved will not precipitate with gelatine 
till after the alkali which it retained is neutralized with 
an acid. The alkaline earths precipitate it, but the 
precipitates are slightly soluble in water; the heavy 
oxides precipitate it in combination as a puce-colored 
substance. On treating the precipitate with nitric acid 
the artificial tannin dissolves without change, whereas 
the natural product is altered by this agent. Heated 
alone in a retort it yields water and nitric acid, ammonia, 
carbonic acid, and another gaseous substance, probably 
nitrogen. 

Composition. 

According to M. Chevreul artificial tannin is formed 

of 

Carbon ^ 

Hiidroqen . 7 . • 7 

^ > ^n undetermined proportions. 

Oxygen 

Nitrogen J 

First Variety. 

Digest diluted nitric acid on powdered charcoal till 
entirely dissolved. The proportions are 

Charcoal . . . . . 1 part 

Nitric acid at 1.40 ... 5 parts. 

Water 10 " 

Mix the acid with the water and treat the charcoal in 
flasks that you heat in the air. A quick effervescence 
takes place due to the disengagement of nitrous acid. 
After a digestion of a few days add nitric acid and leave 
to digest until the carbon is i^issolved. Evaporate to 
dryness and a brown mass is obtained, which is the ar- 
tificial tannin. By this process you obtain 99 grains of 
artificial tannin from 88 grains of charcoal. 



ARTIFICIAL TANNIN. 63 

Second Variety. 

This process consists in treating some substances rich 
in carbon, as indigo, resin, etc., with nitric acid. The 
dissolution of indigo in nitric acid gives a residue with 
an orange color, very bitter, soluble in water, forms with 
gelatine an insoluble precipitate, and has an action simi- 
lar to tannin on metallic salts. This variety contains 
nitrous acid. 

Third Variety 

Is obtained by dissolving camphor and resins in sul- 
phuric acid and leaving them together till the liquor 
becomes black, adding cold water, which precipitates a 
black powder, which is digested in alcohol. By evapora- 
tion a black substance soluble in water and alcohol is ob- 
tained. It forms an insoluble precipitate with gelatine, 
and has a weak action on salts of iron. According to 
M. Chevreul this tannin contains hyposulphuric acid. 

Preparation of a Tannin from Turf. 

Mr. H. C. Jennings has prepared a tannin from turf 
in the following manner: He takes black turf and 
moulds it into small bricks from 2 to 4 inches thick, and 
exposes them to the air until dry. He reduces them to 
fine powder, introduces into a vessel and moistens the 
surface with nitric acid from 10 to 20 per cent, of the 
weight of the turf, stirring well. The mixture becomes 
warm and swells. 

When red nitrous vapors appear he hermetically shuts 
the vessel and leaves until all vapors have disappeared, 
then he adds 6 to 10 times the weight of water and stirs 
well. 

When the mixture is thoroughly homogeneous he 



64 CHEMISTRY OF TANNING. 

treats it with boiling water. The tannin dissolves in 
the water. 

Mr. Jennings has ascertained that leather can be 
tanned with this tannin, but after its use the skins must 
be dipped in a solution composed of 30 to 40 parts of 
carbonate of soda in 100 of water. 



CHAPTER lY. 

TANNIN FEOM VAEIOUS SOUECES. 

It is demonstrated that several substances by com- 
bining with certain acids, produce natural and artificial 
tannin. The combination of an acid is indispensable 
for the existence of tannin, or rather tannin is not an 
immediate principle, but the compound of a peculiar 
substance and an acid united with more or less ex- 
tractive matter. 

1. Thus the tannin of nutgalls, of the barks of oak, 
sumach, etc., is united with gallic acid in greater or less 
proportion. It is very difficult to separate them, and 
we believe that it is to the gallic acid that is due the black 
precipitate formed by tannin in salts of sesqui-oxide of 
iron. This acid plays an active part in tanning. Its 
action has not been yet studied. The older the vege- 
table substances, the more gallic acid they contain, and 
consequently less tannin. 

2. Artificial tannin is always combined with nitric or 
sulphuric acid, according to the acid used. 

3. It is in acid fruits that tannin is found ; in this 
case it is united w^ith gallic acid and even with the acid 
from the fruit. 

Chemists name four kinds of tannin. 



GALLIC AND ELLAGIC ACIDS. 65 

1. Natural tannin, presenting several varieties, accord- 
ing to the proportions of extractive matter and gallic acid. 

2. Artificial tannin resulting from the action of nitric 
acid on charcoal. 

3. Artificial tannin resulting froiii the -action of nitric 
acid on indigo, resins, etc. 

4. Artificial tannin resulting from the action of sul- 
phuric acid on rosin or camphor. 

In the present state of things it is not rational to 
confound artificial with natural tannin, and the above 
statement is sufficient. 



CHAPTER V. 

GALLIC AND ELLAGIC ACIDS. 

GALLIC ACID — PREPARATION — CHEMICAL PROPERTIES — COMPOSITION — 

ELLAGIC ACID. 

GALLIC ACID. 

The tendency of Tannin to be transformed into gallic 
acid has been already mentioned ; but it may be well to 
show more in detail the circumstances under which this 
change is effected, and to point out the properties of 
gallic acid generally, as also with regard to the operations 
of the tanner. Its name has been derived, as is evident, 
from galls, on account of those excrescences containing 
it ready formed. It likewise exists in the cypress nut, 
arnica fioioer 8, ivJiite hellebore, meadow saffron, colcJiicum 
autumnale, and in a number of astringent barks together 
with tannic acid, but in small quantities. Its most 
prolific source is tannic acid, which by oxidation yields 
it abundantly. The conditions affecting the change, 
5 



66 CHEMISTRY OF TANNING. 

such as exposure of the solution of tannin to air and at 
an increased temperature, have been already mentioned, 
as likewise the decomposition of the same body by the 
mineral acids. All the methods recommended for the 
production of gallic acid from tannin are based upon 
these properties of the latter. ^ 

Preparation. 

Sclieeles Process. — He makes a concentrated aqueous 
solution of nutgalls, filters and leaves exposed to contact 
with the air. Tannin is decomposed little by little, and 
gives place to a moulding, which is taken after one or 
two months; he takes out the yellowish or grayish 
deposit from the bottom of the vasis and dissolves it in 
boiling water ; he filters, and by a gentle evaporation, 
obtains gallic acid in the form of brownish crystals. He 
redissolves it several times in boiling water, and purifies 
it with a little animal black. 

Fiedlers Process. — In one pint of water he boils one 
ounce of nutgalls, filters, and adds to the liquor a solution 
of two ounces of alum, the alumina of which has been 
precipitated by carbonate of soda. He stirs the mix- 
ture and leaves it in till the next day. The precipitate 
is treated with hot water until it does not blacken sul- 
phate of iron. He reunites the liquors and evaporates 
so as to obtain crystals by cooling. 

Braconnots Process. — Take powdered nutgalls and 
pour on th,em water in sufiicient quantity to cover them, 
and then leave at a temperature of 70° to 75°. After a 
while a quick action takes place, and when this subsides 
the paste is expressed and treated with boiling water, 
which dissolves the gallic acid and yields it upon evapo- 
ration in impure crystals. These by re-solution in water 
and filtration of the liquid through animal black afford 



GALLIC AND ELL AGIO ACIDS. 67 

a menstruum which gives the gallic acid in a state of 
purity when concentrated. 

Tires Process. — In a strong solution of nutgalls pour 
hydrochlorate of tin until no more precipitate is formed. 
Filter, dilute the matter in water and pass through it a 
current of hydrosulphuric acid gas, filter, evaporate; 
crystals of gallic acid deposit by evaporation. 

It would appear from various researches that the 
change of tannin to gallic acid, on exposing the extract 
containing the former to air and moisture, is due to a 
fermentative process, which is considerably expedited if 
the vegetal matter in the bark or gall, or whatever else 
the source may be, is permitted to remain in contact 
with the liquid. Such is the case, especially with the 
extract of gall-nut; and it may be inferred that the 
tannin from all other source^, and which is capable of 
being transformed into gallic acid by oxidation in the 
above manner, is similarly affected. Mr. Laroche has 
shown by comparative experiments the effect of the 
marcs of gall-nuts after the extraction of the tannin with 
ether in the ordinary way in operating this change. By 
inclosing -an aqueous solution of tannin and a portion of 
this residue in a bottle or flask, and allowing it to remain 
for some time, he found that the tannin was entirely 
converted into gallic acid, whilst a strong extract of 
tannin, freely exposed to the air at the same time, 
retained nearly the whole of its tannin unaltered. Hence, 
doubtless, the insoluble matter in galls in the presence 
of moisture, is capable of acting on tannin as a ferment, 
and that the change of tannin into its derivatives is the 
result of a fermentation. It is well known that fermen- 
tation by contact of yeast, blood, and albumen effects the 
same transformation of the astringent extract as the 
residue of the galls which have been digested in ether, and 



68 CHEMISTRY OF TANNING. 

also /that the latter will excite the various fermentations 
in solutions of grape sugar, and, therefore, these reactions 
may be taken as mutually corroborative. Further, the 
gallic fermentation may be intercepted by antiseptics 
like the vinous. Protochloride of mercury completely 
prevents the decomposition ; and pyroligneous acid, or 
carbonic acid, on account of some aromatic matters which 
it contains, likewise considerably retards the fermenta- 
tion. 

It has been shown that sulphuric and hydrochloric 
acids at a boiling heat rapidlj^ change tannin into gallic 
acid, and without the intervention of air; but if the 
mixture be kept at a common temperature, Mr. Antoine 
has shown by his researches that the decomposition of 
the tannin is retarded by a small quantity of these acids. 
On the contrary, malic, tartaric, and vegetable acids in 
general, expedite the decomposition of the tannin. The 
rapidity with which sumach ferments may be referred 
to the quantity of malic acid it contains. 

Properties. 

When pure, this acid crystallizes in long silky needles, 
which are unalterable in the air ; its taste is acrid and 
styptic. Braconnot states that it dissolves in a hundred 
parts of cold and in about three parts of hot water, four 
or five parts of alcohol in the cold dissolve it, but one 
part of the hot spirit will take it up. It is soluble in 
ether, but in less quantity. The aqueous and spirituous 
solutions, but the former more readily, undergo decom- 
position, so that the surface of the liquid becomes mouldy, 
and a brownish matter is produced, which Daeboereiner 
considers ulmin. Added to a solution of gelatine no 
precipitation occurs, a behavior which at once distin- 
guishes gallic from tannic acid, and which indicates that 



GALLIC AND ELLAGIC ACIDS. 69 

it is unavailable in converting skin into leather. This 
being so, and, as has been already pointed out, tan- 
nin being readily convertible into this body, it becomes 
of the utmost importance to the tanner to guard against 
this transformation, which, in the usual way of tanning, 
is so apt to take place. The researches of Larocque 
have shown that, as regards the tannin from galls, the 
decomposition is completely and readily effected, provided 
the insoluble residuary matter be allowed to remain in 
contact with the liquor containing the tannic acid, and 
it is equally well known that the tannin from sumach 
is liable to decomposition, as well when it remains in 
contact with the insoluble portion of this body as when 
it is separated from it; but independently of the action 
of the residue, the malic acid here plays an important 
part. Though the evidence proving that the insoluble 
portion of the barks, etc., employed in tanning when 
allowed to remain in the tan liquor, does operate in the 
rapid conversion of tannin into gallic acid ; thereby ren- 
dering the former valuable body useless is not definite. 
Still knowing that in the waste tan liquor a large quantity 
of gallic acid is found, it may be safely stated that its 
production is from the tannin, and also is owing more 
to the effects of the insoluble matter of the source of the 
tannin than to any oxidation which takes place during 
the tanning processes. Even those kinds of tannin which 
are incapable of producing gallic acid by decomposition, 
are subject to a metamorphosis which destroys the tan- 
ning agent, and this fermenting action is more readily 
produced where the insoluble matter is left in contact, 
than if the liquor were retained by itself. The only 
benefit that the tanner derives from gallic acid is that it 
aids in swelling the hides, and thus facilitates the ab- 
sorption of the tannin; but when it is considered that a 



70 CHEMISTRY OF TANISTlNG. 

dilute solution of sulphuric or vegetal acids effects the 
same thing quite as well, it will be evident that he who 
relies on the swelling bj gallic acid, and sacrifices a cor- 
responding portion of tannin in its production, suffers a 
considerable loss, and is unable to compete with *those 
who can obviate such a sacrifice. 

At 410° to 420°, according to the observations of M. 
Pelouze, gallic acid is entirely volatilized, producing a 
sublimate of beautiful white crystals and pure carbonic 
acid. If the heat be urged to 464° or 482°, instead of 
the foregoing change, another takes place, in which pure 
carbonic acid is likewise developed. But in addition to 
this a quantity of water is produced, and which runs 
along the sides of the retort, in the bottom of which 
remains a considerable mass of brilliant black insoluble 
matter, which at first sight might be taken for charcoal. 
Is is, however, a true acid, and is called by Pelouze 
metagalUc acid. 

The aqueous solution of gallic acid, upon treatment 
with potash, soda, or ammonia assumes a reddish-yellow 
color, which turns to deep brown by exposure to the air, 
probably by the absorption of oxygen. By the use of 
alcohol as a solvent and certain precautions, definite, 
crystallized, and soluble compounds of the acid with these 
bases may be formed. If the acid is associated with 
tannin, it decomposes nearly all metallic salts. With 
baryta, strontia, and lime, it forms slightly soluble com- 
pounds. Its affinity for magnesia is very strong, and the 
compound which it forms with that earth is insoluble in 
water, but soluble in an excess of acid. Gallic acid is 
also neutralized by alumina. 



GALLIC AND ELL AGIO ACIDS. 71 



[lie acid precipitates 




Soluble salts of mercury 


in orange-yellow. 


" " COPPER 


" brown. 


" " BISMUTH 


" lemon. 


" " LEAD 


" white. 



" " PROTOXIDE OF IRON " blue. 

" " SESQUI " " " dark blackish-blue. 

Composition. 

According to Pelouze crystallized gallic acid is com- 
posed of 

Carbon . . . . 50.10 

Hydrogen . . , . 3.64 

Oxygen . . . . 46.26 



100.00 
Numbers which agree with the formula CyHgOgHO. 
Strecker, however, regards it as a tribasic acid ; thus, 
Ci4HgOio2HO= 3HO,Ci4H3072 Aq, and capable of forming 
salts which correspond with the general formula MO, 
2HO,Ci4H307; "2.^.0, nO,Q,,n,0„ and 3MO,Ci4H307; MO 
being the representative of a metallic oxide. 

As pyrogallic acid, C7H3O3 or CuHgOe, metagallic acid 
C7H2O2 or C14H4O4, ellagic acid C14H2O7HO and other 
derivatives of gallic acid, and, therefore, remotely from 
tannic acid, are of no importance in the making of 
leather, they will not be further dwelt upon. 

ELLAGIC ACID. 

Extract of gall, exposed for a long time to the air, 
contains in addition to gallic acid another acid, insoluble 
in water and to which the name of ellagic acid has been 
given. This latter acid is extracted from the deposit 
formed at the bottom of the vessels by treating it first 
with boiling water which dissolves the gallic acid, and 
then with a dissolution of potash, which dissolves the 



72 CHEMISTRY OF TANNING. 

gallic acid in the state of ellagate of potash. The alkaline 
liquid, when evaporated, deposits the latter salt in the 
form of small crystalline spangles, insoluble in freshwater, 
but dissolving readily in alkaline liquid. Acids separate 
ellagic acid in the form of a slightly yellowish powder. 

EUagic acid is insoluble in water, alcohol, and ether, 
and its composition corresponds to the formula Ci4HgOio- 
It loses two equivalents of water at 248°, when its for- 
mula becomes C14H3O8. The formula of ellagic acid in 
combination with bases being C12H2O7, that of the dried 
acid is, therefore, C^OaHyjIIO, and that of the hydrated 
acid Ci4HA,HO+2HO. 

Ellagic acid is said to be the chief agent that gives 
the hloom to the tanned hide. It will interest the reader 
to know the various derivatives of tannic acid. They 
play no part in tanning, but they are curious as a 
scientific fact. 

Tannic acid Q^^^Oi^- 

Oxytannic acid C15H8O14, generated by the combined 
action of potash and the atmosphere. 

Melanotannic acid C14H6O9, generated by the joint action 
of potash, air, and heat. 

MelanogaUic acid, metagallic C12H3O3, by the sudden ac- 
tion and continuance at a tempera- 
ture of 480°. 

Gallic acid C7H3O5, by the action of air and water 

or the action of heat, water, and 
sulphuric acid. 

Ellagic acid C7H2O4, by the action of air and water. 

Paraellagic acid C7H2O4, by the joint action of water, 
sulphuric acid, and a temperature 
of 285.° 

P^rogallic acid C6H3O3, by sublimation of galls and 
of gallic acid at 410°. 



V 



EXTRACTIVE. 73 



CHAPTER VI. 

EXTRACTIYB. 

The term extract was employed by apothecaries to 
denote that portion of any vegetable substance which 
had been dissolved by digesting it in any menstruum 
whatever, and which had afterwards been reduced to a 
thick consistence by distilling off the menstruum, if valu- 
able, or by evaporating it away if not worth preserving. 
So that originally the portions of plants dissolved by 
water, alcohol, wine, acetic acid, carbonate of potash, 
etc., and afterwards inspissated, were called extracts. 
This is the meaning which the word bears in the Phar- 
macopee Royale Galenique et Chymique of Gharras, pub- 
lished in Paris in 1776. Thus the extract of opium of 
Charras was made by digesting opium, first in water, 
afterwards in alcohol, till everything soluble in these 
menstrua had been taken up. The two solutions were 
mixed, the alcohol distilled off, and the water evaporated 
at a gentle heat. What remained was called extract of 
opium. In process of time, these extracts were divided 
into two sets : namely, watery and spirituous, or gummy 
and resinous, according as the menstruum employed was 
water or alcohol. This distinction was attended to in 
the time of Neumann. Afterwards the term extract came 
to be restricted to what was obtained from vegetables, 
by macerating them in water and evaporating the watery 
liquid to dryness. 

The extracts obtained in this way were generally 
considered as soaps, till Fourcroy and Vauquelin pub- 
lished some observations on the subject in 1790. Ac- 



74 CHEMISTRY OF TANNING. 

cording to them, extract is a substance at first soluble in 
water ; but which, when the solution is exposed to the 
air, absorbs oxygen and becomes insoluble. Chlorine 
gas speedily converts it into a solid yellow substance 
insoluble in water but soluble in alcohol and alkalies. 
They inform us that they examined 12 different extracts 
and found the same characters in all. 

In the year 1791, they published an elaborate analysis 
of the cinchona bark of St. Domingo, in which a great 
many experiments on extracts are stated ; and soon after, 
Vauquelin made a set of experiments on the extractive 
principle of vegetables. Fourcroy, in his General System 
of Chemical Knowledge, published about the beginning of 
the present century, recapitulates the facts ascertained 
by Vauquelin and himself. The extracts from vegetables 
are very complex in their nature, but they all, in his 
opinion, contain a peculiar principle, to which he confined 
the term of extract. According to him it possesses the 
following properties. 

It is at first soluble in water, but rapidly absorbs oxy- 
gen from the air, or other substances capable of yielding 
it. By this absorption it acquires a brown color and 
becomes insoluble in water. It has a strong affinity for 
alumina, and is taken away, and the liquid discolored, 
when alum mixed with an alkali is agitated in a solution 
containing the extract. 

De Saussure afterwards showed that the substance 
called extract or extractive by Fourcroy and Vauquelin 
did not combine with the oxygen which was absorbed, 
but gave out hydrogen to it so as to convert it into 
water. The extractive, therefore, was not rendered 
insoluble by uniting with oxygen, but by being deprived 
of hydrogen. It contains a greater proportion of carbon 



EXTRACTIVE. 75 

than it did when soluble in water, and hence doubtless 
the reason why it assumes a brown color. 

Berzelius has distinguished this brown extractive by 
the name of apotJieme ; it possesses the following prop- 
erties : — 

It is not completely insoluble in water, communicating 
a yellow reddish-brown or red color to that liquid, and 
is again deposited when the liquid is evaporated. But, 
it is dissolved with very great difficulty, and a minute 
portion of it communicates a great deal of color to that 
liquid. Boiling water dissolves more than cold, and the 
excess is deposited as the solution cools. It is much 
more soluble in alcohol than in water, and more soluble 
in hot than in cold alcohol. 

Its best solvent is caustic potash, which dissolves a 
great quantity of it, and assumes a deep brown color. 
The alkaline carbonates dissolve it also. The acids pre- 
cipitate it from these solutions. 

The apotheme, thus set at liberty, combines with the 
excess of acid employed to precipitate it, and acquires 
the property of reddening litmus paper. It has a strong 
tendency to combine with acid bodies ; this, doubtless, 
alters its character. But it is very probable that there 
are various species of apotheme, differing from each 
other according to the plants from which they have 
been obtained, though this subject has not hitherto at- 
tracted the attention of modern chemists. We need a 
set of experiments on this subject, with an ultimate 
analysis of apotheme, in as pure a state as possible, aiad 
extracted from different plants. 



76 CHEMISTRY OF TANNING. 



SECTION II. 

TANNING MATEEIALS. 

Substances which are available for the purpose of 
tanning, embrace a wide range of the juices, barks, 
leaves, roots, fruits, and excrescences of trees; vegeta- 
bles which contain tannin, of one kind or another, may 
be taken into account. In looking over the researches 
and labors of chemists, rjnany hundred substances which 
yield tannin have been discovered ; but practice, or the 
trade, recognize only a few of these ; probably owing to 
the quantity which can be annually produced, their 
yield in tannin, or because they offer some advantages, 
either in making a better leather, or in the time required 
to effect the operation. The tannin and other distinct 
principles in vegetable growth of every kind, are derived 
from the sap or soluble matters imbibed by the rootlets 
from the soil in which the plant exists, and the gases 
absorbed by the foliage. In many plants which elaborate 
tannin, it is met with in small proportions, owing, per- 
haps, to its being only a secondary and not a primary 
secretion. It is found in some vegetables equally in all 
parts, whilst in others, certain parts are richer in this 
substance, the remaining exhibiting only slight indica- 
tions of its presence. The particular portions of plants 
that yield the greatest amount of tannin are, therefore, 
preferred in making leather. 

The following is a list of the materials which contain 
tannin in the largest quantities, and which may be em- 
ployed in the manufacture of leather. 



TANNING MATERIALS. 



77 



Inspissated and Pre- c a 
PARED Extracts. ( C 

Yegetable Excrescences. 



Tree Leaves 



Seeds and Bulbs. 



Woods. 



Roots. 



Barks. 



Kmo. 

Catechu or Cutck. 

Galls. 

of the different kinds of willow. 

of the common oak, Turkey oak, evergreen 
oak, and other varieties. 

of the common heath, and other varieties 
of the same plant. 

Garden artichoke. 

Sloe tree. 

Spotted hemlock. 

Bearherry. 

Several varieties of black and green tea. 

Sumach. 

Grape. 

Hydro-sapathum and wild cornel. 

Hulls of the fruit of the ccesalpina coriaria, 
or divi-divi. 

Bulhs of the savilla maritima. 

Dried acorn hulls of the prickly copped oak. 

All woods of trees, the harks of which yield 
tannin, also afford more or less of this 
substance ; they are scarcely employed. 

Leadwort. 

Malefern. 

Rhatany. 

Leopards bane. 

Marsh rosemary. 

Birch, chestnut, horse-chestnut, sassafras, 
larch, hazel, beech, Lombardy poplar, 
blackthorn, pomegranate, ash, elm, cork 
tree, cinchona, willow, sycamore, tulip 
tree, wattle, oak, sumach, winter bark. 



It will not be uninteresting to state briefly some of the 
properties of the substances mentioned in the foregoing 
table, with respect to their uses for tanning purposes. 



78 CHEMISTRY OF TANNING. 



CHAPTER VII. 

TANNING SAPS — TANNING JUICES — KINO— CATECHU. 
TANNING SAPS. 

It is the general opinion of physiologists, that plants 
receive a considerable part of their nourishment by the 
root ; that it enters into them in a liquid state and 
passes up in proper vessels towards the leaves. This 
liquid is distinguished by the name of sap. In the spring, 
when the buds begin to expand themselves into leaves, 
if we break off the extremity of a branch, or cut into 
the wood of a tree, this sap flows out, and may be ob- 
tained in considerable quantities. It was first examined 
by Dr. Hales; but chemical analysis had not made suf- 
ficient progress in his time to enable him to ascertain its 
constituents. Deyeux and Vauquelin have more recently 
analyzed the sap of different trees. To them we are in- 
debted for most of the facts known respecting this liquid. 
A few additional ones have been ascertained by John. 

The sap in all the vegetables hitherto examined is nearly 
as liquid as water. It always contains an acid, some- 
times free, but more commonly combined with lime and 
potash. Various vegetable principles are also present ; 
of these sugar is the most remarkable, and mucilage. 
Sometimes albumen and gluten, and sometimes tannin, 
can be detected. When left to itself, the sap soon effer- 
vesces and becomes sour, or even vinous when the pro- 
portion of sugar is considerable. 

Hitherto, the sap of a few species of trees only has 
been examined. We are not in possession of any means 



TANNING SAPS. 79 

of collecting tlie sap of the inferior orders of plants. 
The expressed juices of a considerable number of vege- 
tables, indeed, have been prepared for medicinal purposes, 
but those are not sap, but a collection of all the liquid 
substances which the plant contains. At present, then, 
it is not possible to present a general view of the pro- 
perties of sap. The following are the particular species 
in which tannin has been met most abundantly. 

Sap of the Beech Tree (Fagus sylvaticus) . 

Yauquelin collected two different specimens of this 
sap, the first in the end of March, the second about the 
end of April. It has a reddish-brown color, and a taste 
similar to the infusion of tan. It slightly reddens vege- 
table blues. Baryta, ammonia, carbonate of potash, and 
oxalate of ammonia, occasion precipitates in it ; chlorine 
throws down yellow flakes, sulphuric acid blackens it, 
and disengages the odor of acetic acid. Sulphate of iron 
strikes a black, and glue throws down a copious whitish 
precipitate. When gently evaporated to dryness, it 
leaves a brown extract amounting to about -^^-^ of its 
weight, ductile while hot, but brittle when cold, and 
having the smell and somewhat of the taste of newly 
baked bread. It absorbs moisture from the atmosphere, 
and increases in weight about |. Lime disengages am- 
monia, and sulphuric acid, acetic acid from this extract. 
Alcohol dissolves only a small part of it. This sap 
contains the following ingredients : — 

Water, Acetic acid, 

Acetate of lime, Gallic acid, 

Acetate of potash, Tannin, 

Acetate of alumina, Mucous and extractive matter. 

It contains, besides, a coloring matter, which may be fixed 



80 CHEMISTRY OF TANNING. 

on cotton and linen by means, of alum, and dyes them 
of a fine solid reddish^brown color. 

. The sap of the oak contains tannin ; the sap of the 
maple is composed as follows : — 

Ta7inin, Common salt, 

Gallic acid, Salts of lime, potash, and alumina. 

Acetic acid, 

TANNING JUICES. 

The sap passes from the root through peculiar vessels 
to the leaves, where it is altered by a process similar to 
that of digestion in animals, and formed into all the 
liquid substances requisite for the purposes of the plant. 
These liquids flow from the leaves towards the root in ^ 
appropriate vessels, and have received the name of the 
peculiar' juices of vegetables. They differ very considera- 
bly from each other in different plants. They have all 
a certain degree of consistency, and always contain 
much more vegetable matter than the sap. In the 
present state of organic chemistry, accurate details of 
their properties cannot be attempted ; indeed, it is often 
difficult to procure them from any plant, unmixed with 
the sap. They sometimes exude spontaneously, and 
may always be procured in smaller or greater quantity, 
by incisions through the bark of the plant containing 
them. Many vegetable juices contain tannin, and we. 
give below the three most generally employed. 

Kino. 

For a long time the origin of kino was unknown, but 
it has recently been ascertained to be the product of a 
lofty tree growing upon the mountains of the Malabar 
coast of Hindoostan, named Pterocarpus Marsupium, 
belonging to the natural order Fahacece. 



TANNING SAPS. 81 

Kino is the juice of the tree obtained by making 
longitudinal incisions in the bark ; it flows abundantly, 
and is of a red color, and by drying it in the sun, it 
cracks into irregular angular masses, which are placed 
in wooden boxes for exportation. It sometimes comes 
to this country from the East Indies, but more generally 
from England. East Indian kino is usually in small, 
irregular, angular, shining fragments, in size between 
a pin's head and a pea, of a dark reddish-brown or 
blackish color, opaque, very brittle, easily pulverizable, 
and affording a reddish powder, much lighter colored 
than the drug in its aggregate state, and which becomes 
brownish on being kept for some time. It is inodorous 
and of an intensely pure astringent taste. Boiling water 
dissolves a large proportion of it, forming, when cold, a 
permanent intense blood-red solution; and which yields 
with sesquichloride of iron a dark green, coarsely floccu- 
lent precipitate, which is so abundant as to render the 
whole liquid pulpy. Acetate of lead affords a gray 
precipitate, and tartar emetic a gradually formed lake-red 
muddy jelly. Clear water forms with it a clear sherry 
red solution, leaving a crumbly, grayish-red residuum; 
alcohol dissolves about § of it, and forms a deep brown- 
ish-red tincture which is not disturbed by water. It 
contains 75 per cent, of tannin, and a peculiar extractive, 
24 of red gum, and one of insoluble matter. Its aque- 
ous solution precipitates gelatin, the soluble salts of iron, 
silver, lead, antimony, bichloride of mercury, and sulphu- 
ric, nitric, and muriatic acids. 

African kino is rarely seen in commerce ; it exudes 
from the Pterocarjpus erinaceus. The dha tree kino is 
the product of the hutea frondosa, an East India tree; it 
contains from 70 to 90 per cent, of tannin. It is much 
used in India. The Botany Bay kino is the concrete 
6 



8*2 CHEMISTRY OF TANNING. 

juice of the Eucalyptus resinifera, or brown gum-tree of 
New Holland. It is easily powdered ; the powder has 
an amber color; dissolves slowly in cold water, and 
rapidly in boiling water, forming a deep cherry red solu- 
tion, which on cooling precipitates in a copious, brick 
colored deposit, if the solution be made w4th 1 part of 
kino in 25 of water. 

Jamaica Kino. Product of the coccoloba uvifera, grow- 
ing in the W. Indies. It contains 41 per cent, of tannin. 

South American, Columbia or Caraccas Kino, is de- 
rived from the coccoloba uvifera, which grows upon the 
continent as well as in the islands. It is imported in 
heavy mass, and closely resembles the Jamaica kino in 
color, lustre, taste, and other properties. Cold water dis- 
solves 89 per cent, and alcohol 94 per cent. 

Catechu. 

Catechu is another of the same class as the preceding, 
and forms a most useful article for the tanner. There 
are several varieties, which are distinguished by various 
names, such as cutch, terra-japonica, and gamhir. For- 
merly this extract, from its brownish-red color, was sup- 
posed to be a kind of earth, hence the title terra given 
to it. Catechu is extracted from the acacia catechu, a 
tree which grows to the height of 20 or 30 feet, and 
abounds in the forests from latitude 26° to 30°, known 
as the Bornese territory on the Malabar coast, and called 
Cancan. The heart and bark of the wood are boiled in 
water, and the solution evaporated, which leaves the 
astringent extract known as Caucan catechu. According 
to Nees Yon Esenbeck most of the catechu exported 
from Bombay is prepared from the acacia catechu, whilst 
that brought from Bengal is derived from the uncaria 
gamhir, a shrub cultivated in the countries lying on 
both sides of the shores of Malacca. It is obtained by 



TANNING SAPS. 



83 



boiling the wood, bark, and leaves of this shrub together 
with the inspissated juice in water, and evaporating, 
then adding a little sago to give it consistency; it is 
finally exsiccated in the sun, and then cut into square 
or circular cakes to suit the purchaser. Bombay catechu, 
which is the richest in tannin, is of a dark brownish-red 
hue, both externally and internally, and possesses a spe- 
cific gravity of 1.38. Davy examined the Caucan cate- 
chu, and found it to be 1.39 ; he also found in 200 parts 
of this as well as of the Bengal catechu, and known by 
the title Pegu, from the province of Bengal, where it is 
prepared, the following constituents : — 





Caucan 


OR Bombay. 


Pegu or Bengal 


Tannin 


. 


54.50 


48.50 


Extractive 


. 


34.00 


36.50 


Mucilage 


. 


6.50 


8.00 


Earthy residue 


• 


5.00 


t.oo 



100.00 



100.00 



Cooper found in cutch, which is a commercial name 
for catechu — 



Water .... 


12.8 


Tannin . . ... 


4Y.T 


Extractive matter 


.« . . 9.2 


Gummy "... 


.13.6 


Resinous " 


6.8 


Insoluble residue . 


9.9 



100.0 

The genuine catechu, of whatever variety, contains on 
an average about half its weight of tannin, and its effi- 
cacy in converting skin into leather has been estimated 
as being five times greater than the best oak bark ; but 
this seems exaggerated. Besides the real tannin the 
•extractive matter contained in it is another definite 
substance, which is called catechin, or catechuic acid, and 



84 CHEMISTRY OF TANNING. 

which doubtless plays a part in the process of tanning. 
It possesses the property of coloring the leather deeply. 
This body differs from the tannin in being insoluble 
in cold water, although a solution of the tannin of cate- 
chu takes up a small quantity of it. The varieties of 
catechu of commerce are — 

1. Cake Catechu, from its being in circular cakes. 
Their color varies from a light brown to a black, and 
their weight from several ounces to two pounds. 

2. Pegu Catechu. — As already stated, this variety ob- 
tains its name from the province where it is prepared. 
It is generally imported in masses of a hundred pounds 
weight, but as seen in the shops it presents the appear- 
ance of angular, irregular fragments, in double layers 
with leaves between. It has a compact shining fracture 
and a deep brown color. 

3. Bengal Ccttechu is manufactured into rectangular 
cakes, but in the course of transit they become reduced to 
fragments. Externally it has a rusty-brown color, and 
internally the shades vary from a brownish-gray to dark 
brown. 

4. Bombay Catechu. — This variety occurs in globular 
lumps of the size of tin orange jQattened, and two pieces 
generally adhering together. In color it resembles that 
brought from Bengal. 

5. Oamhir. — It is stated by M'Culloch that no less 
than 4600 tons of catechu under the name of gambir are 
produced annually by the Chinese settlers in Rio. It 
takes the name from the shrub which is its source, the 
uncaria or nauclea gambir. It has a deep yellow or red- 
dish-brown color on the outside, but within it is paler, 
and presents a dull earthy fracture. It comes to this 
country in solid masses of about a cubic inch in size. 
EsENBECK, who examined this variety, states that it 



TANNING SAPS. 85 

yields from 36 to 40 per cent, of tannin. Boiling water 
entirely dissolves it. ' . v - 

6. Areca Catechu. — The nut of an Indian palm known 
by this title affords this kind of astringent substances. 
These fruits are macerated with water, and the decoction 
is made, when a better sort of catechu results, known 
by the term hassa, and the semi-exhausted residue, upon 
further treating it with water, affords a solid extract, 
which is distinguished as caury. The former is of a 
black color and intermixed with husks, and the latter of 
a yellowish-brown with an earthy fracture. The caury 
is, of course, inferior to the extract known as hassu. 

With regard to the application of catechu to the manu- 
facture of leather, the natives of India have long prac- 
tised it; but its introduction into the trade in this coun- 
try for a similar purpose is of recent date. Its richness 
in the tanning agent causes its action to be very rapid 
in producing a gelatino-tannate of the substance of the 
skin, or, in other words, of making leather. The qualities 
of the article manufactured from it are not, however, so 
satisfactory as the rapidity of its effects, either to the 
tanner or the public ; for the leather is very permeable 
to water, light and spongy, hard, and of a dark-reddish 
fawn color. The characteristic deposit from oak bark, 
and a few other tanning agents known as bloom, is not 
produced by catechu, and this want is a material objec- 
tion to its use, as the existence of bloom upon leather is 
considered as a kind of guarantee of its goodness. One 
pound of catechu of good quality is capable of producing 
one pound of leather, and consequently, in tanning 
power is equivalent to five of oak bark, or thereabouts, 
as already stated. ^ 



86 CHEMISTRY OF TANNING. 



CHAPTER YIII. 

EXCRESCENCES CONTAINING TANNIN. 
NUTGALLS. . 

There is no other natural product that affords so much 
tannin as those round, hard, woody excrescences known 
as galls. Formerly it was supposed that these were a 
kind of fruit, but naturalists and physiologists have as- 
certained that is not the case, but that they are excres- 
cences or tumors, which form on the branches of different 
trees and vegetables, owing to the puncture of certain 
insects, for the purpose of depositing their eggs. The 
tree which affords those galls that are commonly known 
as nutgalls, is a stunted species of oak — quercus infec- 
toria — which is generally found throughout Asia Minor. 
It grows to the height of four to six feet, has a crooked 
stem, and yields an acorn two or three times larger 
than its cup. The gall flies, which occasion the gall, 
belong to the genus cynips, and, from different accounts, 
there are several species; that which is concerned in 
producing the officinal galls, is the cynijps gallce tinctoriw. 
The female insect of this variety, by means of an ap- 
propriate apparatus, perforates the cortical part of the 
plant, and in the wound deposits her eggs, together with 
an acrid liquor. In two or three days the part is, as it 
were, inflamed, and a swelling appears, and continues to 
increase till it results in a gall. The eggs which are 
inclosed in this excrescence are hatched, and in due time 
the young larvae appear, and develop themselves, being 
supported by the juices of the plant till they become a 



EXCRESCENCES CONTAINING TANNIN. 87 

perfect insect, when they perforate the galls and escape. 
When this happens, the excrescence loses much of its 
astringent principle, and becomes lighter; but if gathered 
or harvested before the entombed insect is completely 
developed, the nuts are not only heavier, but are richer 
in tannin and command a better price in the market. 
Galls gathered before the escape of the insect, have a 
black or bluish shade; but when the insect has left, 
their color is paler, and they generally attain to a larger 
size. To prevent this occurrence, great care is .taken to 
harvest the galls before the insect attains its full growth, 
and eats its way through, leaving them, however, on the 
trees till they have acquired their greatest growth. In 
some parts, the governor, or aga of the district, levies a 
tax on the produce ; and being thus interested in the 
success of the crop, he causes the cultivator to traverse 
frequently the hills and mountains, to report upon the 
advanced state of the galls, and whenever the proper 
growth has been attained, they are immediately collected. 
The selections thus made are known in the market as 
green-galls, and come to this country from Aleppo, 
Smyrna, and the interior of Asia Minor. Those which 
escape harvesting before the entombed insect has attained 
its full growth or emerged, are known as white galls, and 
are imported from the same place. Another kind of 
gall, produced upon the* oaks growing in many depart- 
ments in France, are nearly equal in size to the Asiatic 
green galls, but they are rounder, and possess a smooth 
and in some instances a polished surface. They have a 
brownish color, and rank, in their content of tannin, 
intermediate between the green and white Aleppo galls. 
A variety originating from the puncture of an insect 
allied to the aphis on the branches and shoots of the 
dystylium racemosum, comes from Japan. They are of 



88 



CHEMISTRY OF TANNING. 



an irregular shape, having in some instances both ends 
small, whilst the middle is much thicker, but more 
generally the stem end is the least and the more swollen 
part is nearer the other. Hence they are called apple-galls. 
Annexed are the analyses of samples of Aleppo and 
Chinese galls by Guibourt and Davy. 





Aleppo 


GALLS. 


rjTTTKnJCJlJ /I AT TO 




GUIBOUKT. 


Davy. 


\jl^ 


By Bley. 


Tannin 


. 65.0 


26.0 




69.00 


Gallic acid 


2.0 


6.2 




4.00 


Elagic acid 
Brown extractive 


2.0 
2.5 


— 


fat 

alb'en 

resin 


I 3.00 


StarQh 

Gum 

Sugar 


2.0 
2.5 
1.3 


' 2.4 


cellulai 
matter 


'1 16.00 


Chlorophyl and vol. oil 


0.7 


— 




— 


Woody fibre 
Water 


10.5 
. 11.5 


1 65.4 




8.00 




100.0 


100.0 


100.00 



CHAPTER IX. 

LEAVES— TEA— FLOWEES AND FRUITS— SEEDS AND BULBS. 



LEAVES. 

Or the foliages of trees containing tannin, very few, if 
any, are now employed in the manufacture of leather. 
The leaves of the Jieath were once extensively used, but 
this material has long since been abandoned, preference 
being given to oak barks and other substances of native 
and foreign growth. 



LEAVES, TEA, FLOWERS AND FRUITS. 89 

List of Tanning Leaves. 

1. Leaves of the different species of wiUow : common 
white willow [salix alba), water willow (salix caprea), * 
cracking willow (salix fragilis) , red willow {salix pentan- 
dria), Downy-mount willow (salix arenaria), weeping 
willow (salix hahylonica), Pyrenean willow (salix aurige- 
rana, S. arandifolia, S. pyrendica), black ^ willow (S. 
nigricana)Y shn^r^ leaved willow (S. coesia, S. tanceolata), 
yellow willow (S. vitellina), osier willow (S. incana, S. 
viminalis).-~L~ ■- 

2. Leaves of the service tree (sorhus domestica), and 
mountain ash (S. aucuparia). 

3. Of the pomegranate (punica granafum) . 

4. Of the beech-tree (fagus sylvatica), chestnut tree 
(S. ca.stanea). 

5. Olive tree (olea Eurofce) . 

6. Of the common medlar (mespilus germanica). 

7. Of the common dogwood (cornus mas) . 

8. Of the hazel-nut tree (corylus arellana). 

9. Of the common birch (hetula alnits, B. alba). 

10. Of the red rose (rasa gallica), evergreen rose (rosa 
sempervirens) . 

11. Of the common ramble (rubus fruticosus), dew- 
berry (R. ccesius) , the cloud berry (R. chamoemorus) con- 
tains 7.3 of tannin. 

12. Of the yellow-rooted water dock (rumex aqvaticus). 

13. Of the rosemary (rosmarinus officinalis) . 

14. Of the common European oak (quercus robur), 
Turkey oak (Q. cerris), sessile-flowered oak (Q. sessi- 
flora), hoary oak (Q. toza), Apennine oak {Q. apennina), 
evergreen oak (Q. ilex). 

15. Nearly all the cistus family. 

16. Of the common heath (erica vulgaris), fine leaved 
heath (erica anera), cross-leaved heath (E. tetralix). 



90 CHEMISTRY OF TANNING. 

17. Of the French tamarisk {tamarix g allied), African 
and German tamarisk {T. Africana and Germanica). 

18. Of the garden artichoke {cynara scaly nus), of the 
twigs and leaves of the cynara cardunculus, cardom. 

19. Of the sloe tree [prunus spinosa), common plum 
(P. domestica), briancon apricot (P. hrigantiacd), common 
apricot (P. armeniaca) , sweet almond (amygdalus com- 
munis), common peach {A. persica), common cherry (P. 
cerasus) . 

20. Of the spotted hemlock [conium maculatum) . 

21. Of the horse-chestnut [cesculus hippocastanum) . 

22. Of the crowfoot leaved cranesbill {geranium pra- 
tense) . 

23. Of the common Oenothera, or evening primrose 
{oenotliera hien7iis) . 

24. Of the lime-tree (tilia europcea). 

25. Oi ihe. hQdiYhQ'CTy {arhutus uva ursi) . 

TEA. 

The tea plant is a shrub or small tree, which in a state 
of nature may attain a height of twenty-five to thirty 
feet, but which, when cultivated, seldom exceeds six or 
seven. The tea plant is a native of China and Japan ; 
it is an evergreen shrub from four to eight feet high. 
It is divided into black and green teas. The green tea 
is characterized by a dark green color, sometimes inclin- 
ing more or less to blue or brown. It has a peculiar, 
refreshing, somewhat aromatic odor, and an astringent 
slightly pungent and agreeable bitterish taste. Its infu- 
sion is of a pale greenish yellow color, with the taste and 
odor of the leaves. Blach tea is distinguished by a dark 
brown color, usually less firmly rolled, and lighter than 
the green. Its odor is fainter and of a somewhat differ- 
ent character, though still fragrant. Its taste is astrin- 



LEAVES, TEA, FLOWERS AND FRUITS. 



91 



gent and bitterish, less pungent and less agreeable than 
the green. 

The composition of tea is shown by C. J. Mudler's 
analysis : — 



Volatile oil 

Chlorophylle . 

Wax 

Resin 

Gum 

Tannin 

Thein 

Extractive 

Apotheme 

Muriatic extract 

Albumen 

Lignin 

Salts 



Frank found the tea thus formed 



Green. 


Black. 


o.*r9 


0.60 


2,22 


1.84 


0.28 


— 


2.22 


3.60 


8.56 


1.28 


17.80 


12.88 


0.43 


0.46 


22.80 


19.88 


traces 


1.48 


23.60 


19.12 


3.00 


2.80 


1T.68 


28.32 


6.56 


5.24 



104.94 



103.50 





Green. 


Black. 


Tannin . 


34.6 


40.6 


Gum . . 


5.9 


6.3 


Ligneous fibre 


51.3 


44.8 


Gluten . 


5.7 


6,3 


Yol. matter & loss 


2.5 


2.0 




100.0 


100.0 


FLOWERS AND FRUITS. 






Valonia. . 





Hitherto flowers and flower tops, though containing 
tannin, have not been used in the preparation of leather 
on the large scale. The same might be said of fruits 
with the exception of the acorn-cups of the quercus 
(Bgilops, prickly cupped oak, a tree which grows in abun- 



92 CHEMISTRY OF TANNING. 

dance in the Morea and the adjacent countries. In 
commerce thej pass under the name of valonia, and are 
imported from Turkey, Greece, Italy, and India. When 
the fruit is gathered it is conveyed to the nearest port 
to be shipped, then it is stored in a warehouse during 
several months, being laid out in beds of three to five 
feet in thickness. A slight heating or fermentation sets 
in during the above period, and as the moisture escapes 
the long spreading scales, which hitherto confined the 
acorn, become contracted and allow the latter to fall 
out from the cup. After being well dried the whole is 
picked, and the acorn, which contains no tannin, and the 
damaged cups are separated from those of the latter that 
are dry and good. The cup of this acorn, so long as kept 
dry, retains a bright drab color ; but when exposed to 
moisture, it loses this appearance and turns black, losing 
by the change its tanning properties. Doubtless to the 
long exposure of the upper cups to the disengaged vapors 
from the bed, is owing their being invariably more or 
less damaged. Ordinary or common valonia, the cups 
of which average about 2 inches in diameter, differs from 
that kind known as carnata or carncBtena valonia, 
which are only about the size of a large cherry; the 
latter is said to be the fruit of a smaller species of quercus 
than that which affords the common valonia. It is in 
greater demand for silk dyeing than tanning. 

Leather prepared by valonia is said to be harder and 
less permeable to water than that made with oak bark ; 
and besides it presents the advantage of readily deposit- 
ing a rich bloom upon the leather, a characteristic much 
sought by the traders in this article. Not less than 
10,000 to 12,000 tons of this tanning agent are annually 
used in England, and it is stated that two pounds of good 
average quality are sufiicient for making one pound of 



LEAVES, TEA, FLOWERS AND FRUITS. 93 

leather. Its price varies from $50 to $100 per ton. 
Myrohalans, the dried fruit of various species oi terminalia^ 
is extensively employed in tanning and dyeing factories. 
There are several kinds, all of which come, however, 
from the East Indies through Calcutta and other ports. 
This sort of fruit, when ripe, is pear-shaped, deeply 
wrinkled, of brownish-yellow hue, and weighing from 
70 to 100 grains. The whole of the astringent matter 
which it yields is contained in the husk, which is easily 
separated from the unclosed nut by bruising the whole. 
Besides the tannin, a yellow coloring matter with muci- 
lage and other principles is extracted. This tannin 
differs slightly from that found in nutgalls. 

Divi-Divi is an article which has acquired, within a 
comparatively modern date, an interest with tanners and 
commercial men. It may be classed with the foregoing, 
since it consists of the dried pods of a leguminous shrub 
— Ccesalpina coriaria, which is indigenous to South 
America, and grows to the height of twenty and even 
thirty feet. The pods are about 3 inches long, of a 
dark brown color, and curled up as if they had been 
submitted to a high temperature during desiccation — 
the whole of the tannin is concentrated in the rind of 
the pod, immediately beneath the epidermis, and has 
consequently a very astringent taste, but the inner por- 
tion that includes the seed is very insipid. Besides 
tannin, it yields coloring matter, and a mucilaginous 
substance which interferes with its application in dyeing 
and printing. The leather prepared with divi-divi is 
very porous, and tinged brown or brownish red, accord- 
ing to the density of the ooze, time allowed, and state of 
exposure to the air. Its formation is attributed to a 
fermentative change induced by some of the extractive 
matter; this change occurs as well in cold as in warm 



94 CHEMISTRY OF TANNING. 

weather, but more frequently in the latter. During the 
reaction a reddish matter deposits upon the leather in 
course of preparation, and on the side of the pit. By 
preventing exudation of some of the principles present, 
through the exclusion of atmospheric air, none of the 
fore-mentioned substances appear, and the leather re- 
tains the natural color. A solution or extract of divi- 
divi readily affords a deposit of bloom to leather. Sten- 
HOUSE has shown that the tanning matter of divi-divi, 
though similar to that contained in galls, inasmuch as 
it exerts a like reaction on solutions of sesquisalts of 
iron, is, nevertheless, different from the latter, since it 
produces no pyrogallic acid when submitted to dry 
distillation. 

Of Tanning Flowers and Flower Tops. 

Wild tansy [potentilla anserina). 

Agrimony (agrimonia eupatoria). 

Snakeweed {polygonum historta). 

Malefern {filix mas). 

Wood strawberry [fragaria vesca). 

Dropwort (spircsa filipendula) . 

St. John's wort {Jiyijericum perforatum) , 

Common cotton rose {silago germanica). 

Greater and lesser periwinkle [vinca, major and minoi'). 

Spotted persicaria {polygonum persicaria) . 

Plantain {plantago major). 

Ladies' mantle [alchemilla vulgaris). 

Everlasting [graphalium dimcum). 

Marsh horse-tail (equisetum palustre). 

Common burnet {poterium sanguisorha) . 

Lungwort {lichen pulmonarius) . 

Cinquefoil {potentilla reptans). 

Meadow sweet {sporcea ulmaria). 

Wood cranesbill {geranium, grandiflorum). 



LEAVES, TEA, FLOWERS AND FRUITS. 



95 



Red rose {rosa gallicd). 

Hop {Jiumulus lupulus) contains more than 0.4 of 
tannin and gallic acid. 

Clove tree (Etogenics caryopJiyllata) contains .13 of a 
peculiar tannin. 

Common avens (geum urhanum) is an European plant. 
Its root is verj rich in tannin, and contains,. according to 
Tromsdorff — 



Volatile oil (heavier than water) . 


0.038 


Resin ...... 


3.998 


Tannin (soluble in alcohol and ether) . 


. 40.984 


Adraganthijie ..... 


9.196 


Gummy matter ..... 


. 15.793 


Woody fibre ..... 


. 29.991 



* 100.000 

The water avens [geum rivale) which grows on this 
continent from Canada to Pennsylvania, likewise possesses 
tanning properties. 

Seeds and Bulbs Suitable for Tanning. 

Those of the grape contain much tannin, and give 
very good results. Those of the wild cornel (hydro- 
sapathum). The bulb of the sciUa maritima, a perennial 
plant indigenous to Barbary, Sicily, and Spain. There 
are two varieties of squills, the red and white bulb, but 
they do not differ in property. Before being sent to 
market they are thinly sliced and dried. 

According to Vogel's analysis 100 parts of dry squill 
contain — 



Gnm ...... 


6 


Bitter principle .... 


35 


Tannin ...... 


24 


Saccharine matter .... 


6 


Woody fibre ..... 


29 



100 



96 CHEMISTRY OF TANNING. 



CHAPTER X. 

WOODS— BOOTS— BAEKS. 

Woods. 
This material has not been converted to any useful 
end so far as it immediately concerns tanning, notwith- 
standing, that tannin, as before stated, exists to some 
extent in many species. 

Boots. 

The dentelaria, or leadwort {Plumbago Europcea), a 
perennial herbaceous plant growing wild in the South of 
France, contains a considerable quantity of tannin. 
The MALEFERN {aspidium filix mas), grows in all parts, 
of Europe, and in shady pine forests from New York to 
Virginia. The best root is about 6 inches long and an' 
inch broad ; externally it is of a brown color, internally 
yellowish or reddish white, with a peculiar but not very 
strong odor, and a sweetish bitter nauseous and astrin- 
gent taste. It is collected in May and September. 

MoRiN has analyzed the root and Peschier . the buds. 
Morin found — 

Volatile oil, Tannin, 

Fatty matter comp. of elaine Uncrystallizable sugar, 

and stearin. Starch, 

Gallic acid. Ligneous, 

Acetic acid, Gelatiniform matter. 

Peschier found — 

Aromatic vol. oil, Reddish brown col. matter, 

Aromatic fatty oil, Extractive, 

Adipocerous principle. Acetic acid. 

Brown resin, Chloride of potassium. 

Green coloring matter. 



WOODS^ — ROOTS BARKS. 97 

Rhatant (krameria triandna) is a native of Peru, 
growing in dry, argillaceous, sandy places. It was dis- 
covered in 1780 by Ruitz. It consists of short root-stock 
from half to two inches in diameter. Its bark is dark 
brownish red, wrinkled and warty on the root-stock, 
brittle, inodorous, and of a strongly astringent and 
slightly bitterish taste. The woody interior is yellow- 
ish red, dense, tough, and of the same taste, but much 
weaker. 

According to a recent analysis I made of this root, 
I found it thus formed : — ^ 

Organic matters 93.60 

Inorganic " ....... 6.40 

100.00 
Gum and albumen 1.257 

Sugar . . . . . . . . 0.285 

Extractive 0.628 

• Starch 1.064 

Tannin 3.928 

Coloring matter (resin) 20.5T8 

Soluble salts 0.878 

Insoluble " ....... 5.428 

. Ligneous matter 65.954 

100.000 
Gmelin found 38.3 of tannin, and Peschier 42.6 ; 
but in those analyses they calculate the coloring matter as 
tannin. 

Marsh Rosemary [Statica Caroliniance) is found along 
the sea-coast in marshy situations from Maine to 
Florida, flowering from August to October. The root 
is large, fusiform or branched, heavy, fleshy, and of a 
reddish or purplish brown color. It is inodorous, but has 

Journal of Materia Medica, vol. i., new series, page 141. Analy- 
sis of Rhatany, by Prof. H. Dussauce. 
7 



98 CHEMISTRY OF TANNING. 

a saltish extremely bitter and astringent taste. Accord- 
ing to Prof. Parrish it contains 12 per cent, of tannin, 
some gum, extractive, albumen, resin, volatile oil, caout- 
chouc, lignin, coloring matter, and various salts. 

Barks. 

The bark is the outermost part of vegetables. It 
covers the whole plant from the extremity of the roots 
to the extremity of the branches. It is usually of a 
green color ; if a branch of a tree be cut across, the bark 
is easily distinguished from the rest of the branch by 
its color. If we inspect such a horizontal section with 
attention, we shall perceive that the bark itself is com- 
posed of three distinct bodies, which, with a little care, 
may be separated from each ether. The outermost of 
these bodies is called the epidermis, the middle one is 
called the parenchyma, and the inner one, or that next 
the wood, is called the cortical layers. 

The epidermis is a thin, transparent membrane, which 
covers all the outside of the bark. It is pretty tough. 
When inspected with a microscope, it appears to be 
composed of a number of slender fibres crossing each 
other and forming a kind of network. It seems even 
to consist of different thin, retiform membranes, adhering 
closely together. This at least is the case with the 
epidermis of the birch, which M. Duhamel separated 
into six layers. The epidermis, when rubbed off, is 
reproduced. In old trees, it cracks and decays, and new 
epidermides are successively formed. This is the reason 
that the trunks of many old trees have a rough surface. 

Davy was induced by some observations of Mr. Coats, 
of Clifton, to examine the epidermis of the bamboo, the 
sugar-cane, and the equisetum hyemale. He found in 
them a great quantity of silica. When examined under 
the microscope, the epidermis of these gramineous plants 



WOODS — ROOTS — BARKS. 99 

constitutes a brilliant retiform tissue, which gives it the 
harsh feel by which it is distinguished. The epidermis 
of the bamboo was found to contain 17.4 per cent, of 
silica, and it has the appearance, when pulverized, of 
pounded glass. He found also silica in the epidermis of 
the sugar-cane, the common bog reed {arundo phragmites) , 
wheat, barley, and oats. He found a still greater propor- 
tion of silica in some other of the gramineous plants. 

The parenchyma lies immediately below the epidermis; 
it is of a deep green color, very tender and succulent. 
When viewed with a microscope, it seems to be composed 
of fibres which cross each other in every direction, like 
the fibres which compose a hat. Both in it and the 
epidermis ]there are numberless interstices, which have 
been compared to so many small bladders. 

The cortical layers form the innermost part of the 
bark, or that which is next to the wood. They consist 
of several thin membranes, lying one above the other ; 
and their number appears to increase with the age of 
the plant. Each of these layers is composed of longi- 
tudinal fibres which separate and approach each other 
alternately, so as to form a kind of network. The 
meshes of this network correspond in each of the layers, 
and they become smaller in every layer as it approaches 
the wood. These meshes are filled with a green-colored 
cellular substance, which has been compared by anato- 
mists to a number of bladders adhering together, and 
communicating with each other. 

Fourcroy supposes that the epidermis is the same in 
its nature in all trees, and that it possesses constantly 
the properties of cork ; but this opinion is likely not to 
be verified. The cortical layers seem, at least, in many 
cases, to have a similar fibrous basis ; a basis possessing 
essentially the properties of flax, which is itself merely 
the cortical layers of linum usitatissimum. Common 



100 CHEMISTRY OF TANNING. 

cork, which constitutes the epidermis of the quercus suher, 
is composed of a cellular tissue, whose cavities contain 
a variety of foreign substances, which may be separated 
by rasping down the cork and treating it ^y various re- 
agents, as is done with wood, in order to free the lignin 
from foreign matters. Ten parts of common cork, when 
treated in this way, are reduced to seven. This residue 
was considered by Chevreul as a peculiar substance, which' 
he distinguishes by the name of suherin. 

The properties of suberin have not been yet accurately 
determined, owing to the difficulty of obtaining it in 
a state of purity. Sulphuric acid readily chars it. Nitric 
acid gives it a yellow color, corrodes, dissolves, and de- 
composes it ; converting it partly into suberic acid, partly 
into a substance resembling wax, partly into artificial 
tannin, and partly into a kind of starchy matter. 

Suberin is very inflammable, burning with a lively 
flame, while at the same time it swells considerably, but 
does not melt. When distilled it yields water and a 
colorless oil, then a yellow colored oil. These liquids 
are all acids. If the distillation be continued, a brown 
oil comes over with a little ammonia, and a fatty crys- 
tallizable substance, which does not dissolve in caustic 
potash. During the process, combustible gases are dis- 
engaged, and there remains a porous charcoal, weighing 
i part of the suberin employed. 

Chevreul heated given weights of common cork, washed 
cork, and suberin with nitric acid, and obtained the fol- 
lowing products : — 





Common 
Cork. 


Washed 

COKK. 


Spbekin 


Fibrous, white, insoluble matter 


0.18 


0.9 


1.0 


Resin . . . . . 


14. t2 


1T.5 


10.0 


Oxalic acid . . . . 


16.00 


10.6 


Y.6 


Suberic " , . . . 


14.40 


19.6 


22.4 



45.30 48.6 41.0 



WOODS ROOTS — BARKS. 101 

What is wanting to constitute the 100 parts is a yel- 
low bitter substance held in solution by the mother 
water, too;ether with carbonic acid and water formed at 
the expense of the constituents of cork. 

Chevreul obtained from the epidermis of the birch, 
cherry tree, and plum a quantity of suberic acid, which was 
always the greater the purer the epidermis employed. 
Hence it would appear that these epidermides have a 
constitution analogous to that of cork. According to 
John, the young epidermis of the birch differs essentially 
from cork in this respect. It is soluble by boiling in 
caustic potash lye, and when the brown-colored solution 
is treated with an acid, yellow flocks fall, which become 
brown on drying. This precipitate is slightly soluble in 
boiling alcohol, but most of it falls again when the solu- 
tion cools. The matter of the parenchyma, and the juice 
which exists in bark, vary extremely, and probably oc- 
casion most of the differences between them. Some, as 
oak barks, are characterized by their astringency, and 
contain tannin ; others, as cinnamon, are aromatic, and 
contain an essential oil; others are bitter, some are chiefly 
mucilaginous, others resinous, etc. But in the present 
state of the subject, an enumeration of the different kinds 
of bark is not to be expected ; I shall, therefore, satisfy 
myself with detailing the properties of those barks that 
have been subjected to examination in the art of tanning. 

Cinnamon. — Laurus cinnamomum is a tree growing 
from 20 to 30 feet high, with a trunk from a foot to a foot 
and a half in diameter and covered with a thick scabrous 
bark. This tree is a native of Ceylon, the Malabar coast, 
Sumatra, Borneo. The bark of the root has the odor of 
cinnamon with the pungency of camphor. The leaves 
have a hot taste. The flowers have a disagreeable odor, 
similar to that exhaled from freshly-sawn bones. The 
bark furnishes the cinnamon of commerce. It is usuallv 



102 CHEMISTRY OP TANNING. 

collected from trees about nine years old. The peeling 
commences in May and lasts until the latter part of 
September. The bark is dried in the shade first, and 
finished in the sun. The best bark comes from Ceylon. 
It has a light yellowish-brown color. It possesses a rich, 
pure, peculiar odor, and a sweetish, aromatic, slightly 
astringent, pungept, and peculiar taste. It yields its 
virtues to water and alcohol. Its tannin is of the same 
nature as the catechu tannin ; it gives a dark green pre- 
cipitate with the salts of iron. There are several other 
species of cinnamon, as the C. aromaticum, C. nitidum, 
G. tamala, C. Loureirii, G. culilawan. 

Vauquelin has analyzed two kinds, and found them 
thus formed: — 

Cinnamon of Cayenne. Cinnamon of Ceylon. 

Volatile oil with a smart taste. Volatile oil more agreeable. 
Tannin. Tannin. 

Gum. Coloring matter. 

Salts of potash and lime.^ Gum. 

Resin. 

Sassafras. — Laiirus sassafras is a well-known tree 
growing through the United States and extending into 
Mexico, and flowering in the latter part of April or early 
in May. The flowers have a weak agreeable odor. The 
bark of the root is in small irregular pieces of a grayish- 
brown color outside, rusty-brown within. Hot water and 
alcohol take up its active properties. 

According to Reinsch it is thus formed — 

Water . . . 9.0 Sassafride \ 

Essential oil . . . 0.8 Tannin >- ext. b^ w^k alcohol 6.8 

Fatt9/ matter . . 0.8 Gum j 

Balsamic resin and wax 5.0 Gum, col. matter, and salts 3.0 

Sassafridel extracted by 9.2 Fecula, tannin (hy water) 5.4 

Tannin ) strong alcohol 5.8 Fecula, tannin (by caustic lye) 28.9 

Soluble albumen . , 0.6 Lignin 24.'! 

100.0 



WOODS ROOTS BARKS. 103 

Birch Bark. — Betula alnus, tree which abounds in the 
dry, barren portion of the Middle States, and grows to a 
great height. The epidermis consists of thin white 
layers. The inner bark is astringent, and is used for 
tanning Russia leather. According to Davy it contains 
6.75 per cent, of tannin. Eussia leather owes its odor 
and durability to a fragrant brown oil it contains. 

Chestnut Bark. Castanea vesca. — We have already 
mentioned the chestnut- tree. The American species 
grows in gravelly or sandy soils, and yields a bark which 
contains upwards of four per cent, of tannin. Leather 
tanned with it possesses greater solidity and flexibility 
than that made with oak bark. 

Horse-Chestnut. — JEsculus hippocastanum is indige- 
nous to this country, but is cultivated in Europe. Ac- 
cording to Davy it contains 1.875 per cent, of tannin. 
The American variety is known as Ohio Buckeye. 

Beech Bark. Fagus sylvatica. — Indigenous to the 
North of Europe and North of America. Is very abun- 
dant in New York, Pennsylvania, Kentucky, and Ten- 
nessee. It is classified into two varieties, the white, fagus 
sylvestris — and the red, fagus ferruginea. Beech bark 
is of a silvery color, and contains nearly three per cent, 
of tannin. In places where oak is scarce the white 
beech is used for tanning purposes, and makes a white 
but inferior leather. 

Lombardt Poplar Bark. — Popidus fastigiata contains 
3.12 of tannin, and makes a lighter-colored leather than 
oak bark, imparting at the same time a fragrant odor 
similar to that of Russia leather. 

Black Thorn Bark, — Prunus spinosa, from the sloe 
tree or wild plum tree, contains 3.32 of tannin. The 
black thorn of the United States is the yelloio cratcegtis. 

Pomegranate Bark. — Pwnica granatum is a shrubby 



104 CHEMISTRY OF TANNING. 

tree of African origin. It is cultivated in the southern 
States. There are two varieties, distinguished by their 
fruit ; one is sour and the other sweet. The rind of the 
fruit, the flowers, bark of the root abound in tannin. 

Ash Bark. — Fraxinus excelsior is abundant in our 
forests and grows to a great height. The leaves and 
bark have a very, astringent taste. According to Davy 
the bark contains 3.33 per cent, of tannin. 

Elm Bark. — Ulmus campestris is cultivated in the 
United States, and contains 2.706 of tannin. 

Cinchona Bark grows in South America, and the 
number of species, as described by Guibourt, amounts to 
25, but as many more have been described since. 

As this bark is very costly and used only in medicine, 
we do not think it necessary to describe it here. All 
the cinchona barks are very rich in tannin. 

Poison Oak. — Rhus toxicodendron is a creeping shrub 
from one to three feet high. The leaves are inodorous, 
have a mawkish acrid taste, and yield their virtues to 
alcohol and water. It grows wild through the United 
States. This plant contains tannin and gallic acid. 

Sumach. Rhus glahrum. — In its purity it consists of 
the powdered leaves of a shrub that grows extensively 
in the South of Europe, in the United States and in Asia, 
to which it is indigenous. It seems that there are several 
species, such as the Wild Olive, Rhus cotinus, rhus gla- 
brum or coriaria, which is the best and most esteemed 
for the preparation of the finer kinds of leather. Italy, 
Sicily, Portugal, Spain, and France produce considerable 
quantities of sumach, varying in quality, and distin- 
guished from one another by the habits of the tree, the 
color and other properties. The sumach obtained from 
the rhus coti7ius is for the most part employed in dyeing, 
and the product of the rhus coriaria is that which is 



WOODS ROOTS BARKS. 105 

converted to the uses of the tanner, especially in the 
preparation of morocco and similar leather. The latter 
shrub, which grows wild in Portugal, Spain, and other 
countries named above, rises to the height of four to 
eight and in some cases to 12 feet; its stem is crooked 
and covered with a reddish-gray bark ; the leaves present 
a green on the upper, and a whitish color on the under 
surface during spring and summer, but they assume a 
reddish hue in autumn. It flowers in July, the blossom 
being greenish- red, and yields a cluster of small crimson 
berries on ripening. Regarding the effects of sumach 
as a tanning agent, it is stated that it deprives the skin 
of much of its softness and elasticity, but it offers a great 
advantage of not coloring it during the process, and is 
on this account preferred in France and other places, 
notwithstanding its cost being much greater than other 
tanning agents, by the fabricators of morocco and glazed 
leather. It is utilized in the ordinary way of tanning 
mixed with bark or other matters, and affords good 
results. 

Of the species of sumach in the market, the Sicilian is 
accounted the best. There are two kinds, one of which, 
the alcamo, is the most esteemed. It is a very fine light 
green powder, containing very little woody matter, 
having an agreeable odor analogous to that of the violet 
and a strong astringent taste. It contains very little 
coloring matter, though it gives a yellowish-green solu- 
tion when macerated with water. The second variety 
inclines to a reddish-yellow, has a feebler odor, with a 
less astringent taste than the foregoing variety. Sicilian 
sumach is generally packed in bales weighing about one 
hundred and a half. 

Spanish sumach is various in quality, being less care- 
fully prepared, and, consequently more, or less mixed 



106 CHEMISTRY OF TANNING. 

with woody matters. The best sort comes from Priego, 
and is grown in the neighborhood of Mahvga. It is, like 
the Sicilian, finely ground, and affords a color of equal or 
greater brightness ; its odor reminds one of the tea plant. 
With water it gives a dark and more reddish solution 
than the foregoing. It is usually packed in bales of one 
hundred weight; the other sort, the Molina and Valla- 
dolic sumach, are next in quality to the foregoing; they 
are very similar. 

Portuguese or Porto sumach is almost similar to the 
Priego, but is generally dirtier, and contains more 
mineral salts 

Italian sumach has a dark green color, is free from 
woody matter, but feels granular in the hand, and has an 
odor like that of the bark, which possesses similar 
qualities to the leaves. 

French sumach is similar to the preceding. Three 
sorts are collected : the fauvis is almost equal to the Sici- 
lian when well purified, and comes from Brignolles, 
near Marseilles. If less care be taken in its manufacture, 
it approaches more to the quality of Malacca sumach — 
it frequently goes under both these names. A second 
sort, Donzere, and a third Pudis, are commonly used 
in the tanneries. A fourth variety, called ixdou or recloul, 
obtained from the coriaria myrtifolia, cultivated in Lan- 
guedoc, is of a grayish green color. 

Willow Bark. Salix alba. — This bark is remarkable 
for its astringent taste. This tree grows in the north- 
ern and temperate parts of North America. The dry 
bark has an ash-gray color on the upper and a reddish 
yellow on the under surface. The white willow con- 
tains 2.3 per cent, of tannin and the Leicester willow 
6.86 per cent. The black willow is the most common 
American willow, and grows in the Western and Middle 



OAK BARKS. 107 

States. In the North of Europe the S. alha is used for 
tanning. 

The leather which is made from kid and lamb-skins 
owes its agreeable odor to the willow bark with which 
it is tanned. 

Tamarisk — Tamarix gallica — is a shrub plant indi- 
genous to Spain, Italy, and the South of France. The 
bark is deep reddish brown on the upper and yellowish 
on the under side ; both the wood and bark have an as- 
tringent slightly bitter taste. 

Hemlock Bark. Ahies canadensis. — This tree some- 
times attains the height of 30 feet, with a trunk two or 
three feet in diameter. Its foliage is delicate bright 
green above and. silvery white underneath. Hemlock 
is abundant in Canada, Nova Scotia, and the elevated and 
mountainous regions of New England and the Middle 
States. Its timber is very coarse grained, and its bark 
contains an astringent principle. The bark is largely 
used in this country as a substitute for that of the oaks 
in tanning. It imparts its red color to leather made with 
it, which is said to be inferior to that made with oak 
bark ; but the two kinds "united are supposed to produce 
better leather than either of them alone. 



CHAPTER XI. 

OAK BARKS. 

The oak, by its strength and greatness, is the patriarch 
of the forest. It lives three or four hundred years, 
and some authors have ascertained that it has lived six 
hundred years, according to the fertility and exposure 
of the ground. It is, and will always be, the most use- 



108 CHEMISTRY OF TANNING. 

ful.of trees. It seems that such a -tree ought to be well 
known in its botanical, physical, and industrial cha- 
racter; but such is not the case, and unhappily all the 
varieties of oak are not yet known. The different species 
of oak belong to the noncEcia polyandria ; all the parts 
and principally the bark contain tannin. We shall 
divide them into two classes : — 

1. European oaks. 2. American oahs. 

1. European Oaks. 

Quercus rohur. — This bark, so long and universally 
employed for tanning leather, has been but imperfectly 
examined, Davy found that 100 parts contain 12.7 
parts of extractive and 6.3 of tannin. It contains also 
a considerable quantity of pectin. When oak bark, 
after having been exhausted by tanning, is put into water 
a kind of fermentation takes place, and an acid liquid is 
formed, which is employed in one of the preliminary 
processes of tanning. The acid thus formed is the lactic, 
and the liquid, called jusee by the French, contains ace- 
tate of lime, tannin, apotheme, a gummy matter, free 
acetic acid, and a great quantity of lactate of lime together 
with lactate of magnesia, potash, ammonia, and probably 
of manganese and iron. 

Quercus nigra.)^t 

Quercus glomerata. 

Quercus lamiginosa. >ui<7Vt-, 

Quercus laciniata.yl „ 

Quercus vimivaUs.\ s 

Quercus peduncitlata contsiinB about as much tannin 
as the quercus robur. 

Quercus cerris. jjQ 6 

Quercus haliphoeos. 

Quercus tauza.^ Cyy^^i/K)*^'' 



OAK BARKS. . P • 109 

Quercus esculus groWs in Italy and Dalmatia. 

Quercus apennina grows in Italy and the East. ^-Q.fsAyy^ 

Quercus lastigiata grows South of France. 

Quercus lusitanica. tj.*-*'- " 

Quercus infectoria. ^JljtAjT . 

Quercus Ilex grows in Spain, Italy, and the South of 
France. Is much used to tan leather. 

Quercus suher grows in South of Europe, principally in 
Spain. It requires dry and warm lands and fears the 
damp cool. Its height is from 24 to 30 feet. Its bark 
is very thick and soft and is known by the name of . 
cork. It falls naturally every seven or eight years. It 
is used for tanning and burning, and after the tree has 
attained the age of thirty, the bark is collected regu- 
larly every seven or eight years to manufacture the 
cork. M. Chevreul has analyzed it and found it thus 
formed : — 



Wax. 


Gallic acid. 


Cerine. 


Suberin. 


Soft resin. 


Acetic acid. 


Red coloring matter. 


Brown nitrogenized matter. 


Tannin. 


A salt of lime. 



Quercus coccifera is known by the name of dwarf 
oak and garouille. Its height is from 3 to 4 feet. The 
bark of the root is very rich in tannin and much used 
in Europe for tanning. It is on this oak that grows 
the vegetable Tcermes called vermilion, Coccus llicis. Ac- 
cording to M. Bosc, the leaves and trunks can be used 
in tanning. It is much used in the South of France. 

When this bark is used, the ox-hides are placed 
about 40 in a vat with plenty of water. In the vat 
is first put a small quantity of bark. Increase pro- 
gressively the quantity of bark until about I of the 
bark destined to tan the hides is used. During the time, 



110 • CHEMISTRY OF TANNING. 

which lasts three months for heavy leather, draw and 
drop the hides, and put them back in the liquid. Leave 
them again three weeks, when draw them to put them 
into the pits. 

The barking of this tree is done in every season; 
however, it is richer in tannin in the spring. In June 
it contains 8.9 per cent, of tannin, and in September 
only 8.3 per cent. 

2. American Oaks. 

White Oak. Quercus alba. — This tree varies in size 
according to the climate and soil, attaining the height 
of from 60 to 90 feet with a diameter of from 3 to 6 feet. 
It grows throughout the Union, but is more abundant in 
the Middle States. Its wood is strong and durable, and 
is extensively employed in ship building, etc. The 
bark is employed for tanning, but the red and Spanish 
oaks are preferred. The bark contains much tannin ; it 
has a light yellowish brown color, a feeble odor, and a 
strongly astringent bitterish taste. 

The black oak is a forest tree common to the United 
States, the bark of which is much used in tanning. It 
is preferable to the above. Its coloring principle is 
known by the name of quercitrin. 

The red oak is more common in the Northern States 
and Canada ; its wood is reddish and coarse-grained, and 
used principally for fuel. It contains considerable tannin. 

Quercus Phoellos grows in North America, its height 
is about 100 feet. 

Quercus primus is found in North and 'South Caro- 
lina. Its height is about 99 feet. 

Quercus aquatica grows in North and South Carolina. 

Quercus coccinea, or scarlet oak, is more abundant in 
the Middle States, and on the mountains of Carolina 



OAK BARKS. Ill 

and Georgia, but is found as far north as latitude 43. 
Its height is about 80 feet and its diameter 3 or 4. Its 
leaves are of a beautiful green, and the first frost turns 
them a bright scarlet color. This tree produces galls, 
which are applied to tht same purposes as the European 
galls. 

Quercus virens, or live oak, is confined to the vicinity 
of the Atlantic coast, south of latitude 37° and of the 
Gulf of Mexico as far as the river Sabine. Its height is 
from 40 to 50 feet, and its diameter from 1 to 2 feet. 
The leaves have a dark green color above, and whitisli 
beneath. 

The bark is hard and thick, and of a blackish color. 
It is very good for tanning leather, but is not much 
employed. 

Qiierctcs falcata, or Spanish oak, inhabits all those 
parts of the Union which are south of the 41st parallel 
of latitude, but is most abundant in the Atlantic States. 

This oak is remarkable for the great dissimilitude 
which exists in its leaves and general appearance in 
different climates. In the Southern States it grows to 
the height of 30 feet with a trunk 4 or 5 feet in dia- 
meter, while in New Jersey it is never above 30 feet 
high, with a trunk 4 or 5 inches thick. The bark is 
thick, black, and deeply furrowed, and the wood is red- 
dish and cross-grained, with open pores. The leaves on 
the tree in the South are falcate, and as well as the 
young shoots to which they are attached are covered 
with a thick down upon the under sides. In New 
Jersey the leaves are three lobed, except a few upon 
the summit, which are slightly falcated. This tree 
fructifies once in two years. Its flowers put forth in 
May, and are succeeded by small round brown acorns, 
contained in scaly, shallow cups, supported by peduncles 



112 CHEMISTRY OF TANNING. 

^ of an inch in length. The Spanish oak is chiefly 
valuable on account of its bark, which is preferred to 
any other for tanning coarse leather, which it is supposed 
to render whiter and more supple. The quality of the 
leather prepared with it is sai4 to be improved by the 
addition of a small quantity of hemlock. 

Quercus ambigua, or gray oah, is abundant in Maine, 
New Hampshire, and in Vermont. Its height is 50 to 
60 feet, and its diameter 15 or 18 inches. The leaves 
are large and smooth. It flowers in May. The wood 
and bark are similar to those of the red oak, and the latter 
may be employed in tanning. 



CHAPTER XII. 

BARKING OF THE TREES. 

PART OP THE BARK CONTAINING THE MOST TANNIN — AGE OP THE TREES 
RELATIVELY TO THE RICHNESS IN TANNIN FROM THEIR BARKS — BARK- 
ING OF THE TREES — INFLUENCE OP THE SEASON AND LOCALITIES, IN 
THE TIME OP THE BARKING. 

Parts of the Barh containing the most Tanfiin. 
We have already stated that bark is composed of 4 
parts; all are not equally rich in tannin, or rather some 
contain none. Such is the case with the epidermis, the 
liber contains very little. It is in the inner layer of the 
cortex that it is principally found. Davy has found in 
oak bark of middling size and cut in the spring 0.604, 
while the inside white layers have given him 0.15. The 
experiments of tanners have demonstrated the fact. We 
see then theory and practice agree together. This re- 
mark is of much interest for the tanner who ought to 
reject the bark, with a thick epidermis, as poor in tannin. 



BARKING OF THE TREES. 113 

It is the same case with medicinal astringent barks. 
Indeed quinquina barks are as poor in tanning princi- 
ples, quinia and cinchona, as they are more fibrous or 
ligneous, while if the break is less fibrous, smoother, with 
a resinous aspect, they are richer in those principles. 

Age of the Trees Relatively to the Richness of their Barhs 

in Tannin. 

It is a great mistake, which unhappily is believed by 
a great many, that the older the bark the poorer in 
tannin, however, while we have no doubt our opinion 
will be regarded as erroneous, we do not hesitate to say 
that the older the hm^h the richer it is in tannin. In this 
country this fact has been well understood as tanners 
use only barks of old trees. In Europe they employ 
only young trees from 18 to 30 years old. There is 
great variance of opinion regarding the age of oak to 
give a good b.ark. In some places they bark after 10 
or 12 years, in some others they require a bark 20 years 
old. In this country we use barks, no matter how great 
their age, with the conviction that the tanning part never 
loses its properties. If the bark is covered with moss, it 
is taken out with the black and rough parts. 

In some countries they bark the trees while standing, 
in others they bark only after being cut. This last 
method is the best, for in barking the tree while standing 
they cause a considerable damage to the woods. How- 
ever, according to Bufibn, if the tree must be cut a short 
time after, it is no harm to bark while standing. 

Barking and the Most Convenient Time for it. 

Experiment has demonstrated that it is in the spring, 
when the sap is in full activity, that the bark should be 
8 



114 CHEMISTRY OF TANNING. 

taken. We have said that all the regenerating and 
vivifying power resided in the bark. The suckers, the 
slips, the buds present us a proof of this first fact. Wil- 
low, olive trees, mulberries, and a multitude of others, 
the trunks of which are entirely rotted and the bark 
alone forms the partition. These trees, full of strength, 
are covered with leaves and flowers. This is due to the 
great quantity of nutritious juices conveyed by the bark. 
These abundant juices are sometimes different from those 
of the wood. Often, also, while of the same nature they 
are in so great a proportion that they break the bark to 
exude, or it is sufficient to make some incisions to have 
them run out. Almond trees, acacias, apricot trees, etc., 
are an example. It results from these facts, that while 
the sap is abundant in the bark in the spring, princi- 
pally towards May, it is the proper time for barking. 
Tannin, as we have demonstrated, exists in the sap of 
several vegetables, and independently of numerous experi- 
ments of tanners, which demonstrate the {Superiority for 
tanning of the bark cut in the spring, chemical analysis 
throws light on this important fact. Indeed, Davy has 
demonstrated that 

Oah hark cut in the spring contains of tannin • 6. 04 
" ' fall " " " . 4.385 

Which gives nearly 3 more in the spring. Here again 
theory agrees with practice, both command to choose the 
spring as-the time when the bark is richer in sap and tan- 
nin. Then we must cut every kind of oak at the time 
when the sap is up, and the barking must be done imme- 
diately by cutting circularly the bark from the trunk at 
both ends, and splitting it longitudinally. The bark is 
dried slowly in the shade. 



BARKING OF THE TREES. 115 

Injluence of Seasons and Place at the Time of Barking on 
the Richness in Tannin. 

We have said above that the spring is the best time 
to bafk, but this time may be more or less advanced 
according to the temperature. Thus, if the winter has 
been severe and the spring cold, it will be only in the 
middle or the end of May that vegetation will begin, and 
the barks will not be so rich in tannin. On the contrary, if 
the winter has been mild and the spring warm, April is 
the most convenient time. In temperate climates it is 
by the end of April, or the beginning of May, that this 
operation takes place. The barks are as much richer in 
tannin as they come from trees of warm countries, i. e., 
the tannin is developed in greater proportions the further 
south it is. In the same locality oaks well exposed to 
the south and in dry and elevated places give barks 
richer in tannin. On the contrary, if they are in the 
shade in a low and damp locality they contain less. It 
is the same for rainy seasons which have great influence 
on the production of tannin. The barks are aqueous 
and sur-saturated with vegetable matter. These facts, 
while apparently trifling, are of great interest to tanners. 

Decrease in Weight of Smooth Bark when Exposed 
to the Air, 

Every tanner knows that his bark is somewhat heavier 
when it first comes from the store, than after it has been 
exposed for some time to the sun and air, and that it is 
therefore more advantageous to sell it before it leaves 
the store, instead of after it has lost some of its weight 
under the above circumstances. It will also be to his 
interest to learn how great a loss in weight the stored 
bark is liable to, when placed in the open air. 



116 CHEMISTRY OF TANNING. 

In order to ascertain this, Professor Nordlinger* 
allowed a bundle of smooth bark, weighing about 29 lbs., 
brought from the Hohenheim bark forests, which had 
reached its 15th year of growth, and whose strongest 
limbs were slightly split at the foot, to remain laid flat in 
a plastered room, having little draught through it, during 
May and June. On the 26th of June he took the bark out 
at about eleven o'clock in the morning, and exposed it, 
loosely spread out on trestles, to a tolerably strong wind, 
and a bright but not very warm sun heat — temperature 
75° in the sun, and 72 J° in the shade — and found, after 
weighing it again, that he had sustained a loss in weight, 
that is to say, a loss in moisture of 0.187, upon the 
store weight, and 0.191 after being dried by the wind, 
being about 2 per cent, of the weight of the bark. 

In order to determine the degree of loss that a more 
thorough drying would cause, the small bundle of bark 
was again taken out of the store-room on a warm cloud- 
less day, the 14th of July, and laid upon the ground in 
the open air as before, where it was allowed to remain 
from 9 o'clock in the morning until half-past two in the 
afternoon. The sun was quite strong, 93° in the shade, 
and 9 7 2° in the sun, with little motion in the air. The 
loss in weight this time amounted to 0.383 upon the 
original weight, and 0.398 upon the first drying, 
making an average of four per cent, upon the bark's 
weight. After this, the bark was laid in a balcony 
entirely exposed to the sun, and covered with black 
shingles, making it close and warm, and after being 
allowed to dry there for another hour, there appeared a 
loss of 0.459 upon the original weight in the cool store, 

* Gerber Zeitung. Berlin, Prussia. 



PLANTS CONTAINING TANNIN. 117 

and 0.481, when compared with the sun-dried weight, 
being on the average a loss of 5 per cent. 

The above figures will correspond to most cases. If 
the smooth bail^ is taken out of a cool store and allowed 
to remain in the sun during a few hours, or if it is 
left in the forest over night, and not upon the earth 
where the dew may moisten it, but upon trestles eleva- 
ted about a foot from the ground, it will lose about 2 per 
cent, of its weight in the first event, and becomes heavier 
in the latter. The difference will be greater, perhaps 4 
or 5 per cent., if the bark is exposed to a stronger or 
longer-continued sun heat, or if it is allowed to remain 
on the low ground, or upon staves, as happens when 
bark is peeled in fine summer weather, and the binding 
together of the bundles deferred until evening. 

We consider it obvious, that if the sun-dried bark is 
allowed to lie carelessly upon the ground where the dew 
has fallen, greater fluctuations, impossible to calculate in 
advance, may be the result. 



CHAPTER XIII. 

PLANTS CONTAINING TANNIN USED AS SUBSTITUTES 
FOR OAK BARK.* 

Owing to the great lack of tanning materials which 
was felt several years back, and which gave rise to a 
multitude of experiments with native and foreign sub- 
stances containing tannin as a substitute for oak bark, 
the general committee of the Bavarian Agricultural 
Society of Munich instituted a careful testing of those 
plants which seemed most adapted to supply this 
deficiency. The Gemeijmuizige Wbchenschri/i (No. 42), 

* Geraeinnutzige Wochenschrift. 



118 CHEMISTRY OF TANNING. 

published at Wartzburg, contains the principal agricul- 
tural and chemical experiments there made, and we ex- 
tract from it all which have reference to oak bark and 
its substitutes. 

Plants which are intended to yield a substitute for oak 
bark must be susceptible of cultivation in large quanti- 
ties, and the cost of cultivation and product should stand 
in such a proportion to the price offered by tanners 
that its culture may remunerate the farmer. To this 
end three species of plants, the common snakeroot, or 
adders ivort, the tormentil and the turmeric (but at first 
only the two first) were tested as to their cultivation 
and tanning properties. 

The snakeroot cannot be well propagated from seeds, 
as many of these rejmain unripe or do not bud, and the 
ripe ones need from two to three years before they germi- 
nate, which is a great drawback. Therefore, it is neces- 
sary to take old roots and sprouts, cut them up with the 
seed capsules and lay them in furrows as potatoes are 
planted. This plant always requires a moist soil and 
can only be cultivated in ground suited to it ; in clay or 
sandy soil it does not thrive at all. At Munich a lot of 
moist ground produced the following in one day's gather- 
ing, 16 cwt. of roots, 16 cwt. of leaves, and 8 cwt. of re- 
fuse, which together contained 4 cwt. 80 lbs. of tanning 
material, or 12 per cent, of the gross product, while the 
bark of oak saplings yields 15 per cent. Fraas reckons 
the net product per day's work, after deducting the cost 
of culture at about $4, which does not seem very tempt- 
ing when we contrast it with potatoes, and consider the 
risk of sale. 

The tanning experiments made with snakeroot, by 
Mr. StBeicher, a tanner of Munich, give the following 
results as compared with tanning made with oak and 



PLANTS CONTAINING TANNIN. 119 

hemlock barks. A slower tanning, a pale color, a lesser 
weight, and less firmness in the leather. One great dis- 
advantage of this root in tanning, is the great quantity 
of starch flour that it contains, which forms a pasty sort 
of slime upon the hides which prevents the tannin from 
penetrating thoroughly. These experiments were made 
with roofs of the crop of 1859. In 1860 the product of 
the crop was handed over to Mr. Kester, superinten- 
dent of factories at Munich, who made experiments 
similar in result to those of Mr. Streicher. 

The tormentil grows everywhere, in meadows, heaths, 
and in light wooded grounds. Its roots form a hard 
tuberqle varying in bulk from the size of a hazel-nut to 
that of a chestnut, having leaves similar to those of the 
strawberry plant, and the same sort of blossom, only of a 
yellow color. It contains about 16 per cent, of tanning 
material. The seeds are generally barren, and even 
when they germinate they require at the least two years' 
time to form a bulb of the size of a hazel-nut ; more- 
over, they need a moist soil, and one enriched by decayed 
vegetable matter, a requirement which cannot be filled 
except by breaking up meadows or moor lands. They 
can be raised like potatoes from root eyes ; but these 
eyes require three years before they come to a service- 
able bulb, and moreover they are very difiicult to cut off 
even with a sharp knife. 

This will be sufficient to make it understood that this 
plant cannot be compared with the easily cultivated 
barks of the oak and fir. Reckoning the percentage 
according to the table, it takes only 123 i parts of young 
oak bark to effect the same results, for which tormentil 
root requires 8451 parts, or seven times as much of the 
latter to reach a like degree in the fermentation of the 
leather. Fraas, on his side, reckons that dry tormentil 



120 CHEMISTRY OF TANNING. 

roots could be sold at about $1.25 per cwt. ; but he doubts 
whether the grainer could produce it for that price. In 
addition to this Mr. Kester remarks that the leather 
tanned with tormentil is inferior in quality to that 
tanned with oak bark. 

These interesting experiments, although they turned 
out negatively, are followed by still more instructive 
experiments upon the produce and tanning contents of 
the oak bark forests, in the palatinate and in central 
Franconia, facilities for the same having been accorded 
to the superintendent, Dr. Praas, by the royal minister 
of woods and forests. This, bark came from the forest 
districts of Ammer, Pirmaseus, Twerbrucken, Laute- 
recken, and Spier. VDr- Fraas tested the quality of tan- 
ning material therein contained, according to Muller's 
method ; and in connection with their soil, age, time of 
stripping, etc. The following deductions are drawn : — 

1st. The bark of oak grown in a sandy soil indicates 
everywhere a small content of tanning material (6 to 8 
per cent.), especially in the forest districts of Twer- 
brucken and Ammer. The adjoining districts not only 
offer a poor sandy bottom of mottled sandstone, but they 
are situated at the highest point of land above the level 
of the sea in the palatinate. 

2d. Trees grown on moorland are very rich in tan- 
ning material, containing about 21 per cent, at the age 
of twenty-two. 

3d. Bark twenty years old is quite as rich, and still 
more tannin is obtained from that grown in a clay soil. 
The rich bark grown in the district of Schafferstadt is 
aided by the mild climate, and owing to the vicinity of 
the Rhine, by an underground dampness together with 
a deposit of best old Rhine soil. 

4th. Roll barks from trees twelve to twenty-three 



PLANTS CONTAINING TANNIN. 121 

years old is richer in tanning material than the bark of 
twigs and branches. 

5th. The middle part of good sized trunks contains 
more tannin stuff than the top or the lower part in trees 
from eighteen to twenty-two years old ; but in trees ten 
years of age the top is the richest part. 

6th. A mixture of the two seems advantageous to 
improve the tanning material. 

7th. Barks, stripped from trees ten to sixteen years 
old, contained from 11 to Hi per cent, of tanning ma- 
terial; from twenty to twenty-five years, 12 per cent.; 
and from thirty to forty years, Hi per cent. Exception 
to this occurs from causes relating to climate and the 
condition of the soil. 

8th. The amount of tanning material contained in 
bark, stripped off in the spring, is much greater than 
when it is peeled in summer and in autumn. 

9th. The quantity of tannin held in young firs, grown 
in Central Franconia, is considerable, and the quality 
very good. 

10th. The tanning material of young oak bark is so 
excellent in its effects that it cannot be equalled by any 
other sort of tanning material, and in nowise by snake- 
root or tormentil root. 

To this we shall add that bark oak is sold at a higher 
price per cord than that peeled, because the heat given 
by it is quite equal to that of beech wood, and the char- 
coal produced by it is even preferred, in the foundries 
there, to the charcoal made from beech wood. 

Barked oak burns in a dry state without crackling 
like birch wood; so that what it lost in the volume of 
the cord by peeling off the bark, is made up by the high 
price obtained. Therefore in places where t^ey grow 
cultivated oak bark forests are most profitable. But tan 



122 CHEMISTRY OF TANNING. 

bark containing 8 per cent, of tanning material, by com- 
parison with tan bark containing 12 per cent., is not one 
third less in value, but one-half, because the cost of pro- 
duction and the tanning manipulations render this 
product disproportionally dearer, and still the heavier loses 
less in weight. The tanner's test of tan bark is the 
w^eight of his hides and the time taken to tan them, for 
time lost is money lost. 

M. Briigl, of Ipsheim (Central Franconia), has compiled 
a most admirable work, giving fully the cost of procuring 
and a calculation of the return upon bark peeled in the 
oak and pine forests of his district. We are not able at 
present to give a comprehensive extract from this ad- 
mirable book, which is well worthy of perusal. 

1st. One hundred well-grown, fine-conditioned oak 
trunks, 16 feet long and I2 thick were stripped, and the 
difference in the net proceeds amounted to 28 cents higher 
than for one hundred unpeeled. 

2d. One hundred trunks 12 feet long and one thick 
were peeled and yielded 9 cents more. 

3d. A cord of oak wood was stripped and lost I of the 
cord measurement, despite which, counting the value of 
the tan bark, $1.58 more per cord was obtained. 

4th. One hundred fagots after being peeled showed a 
loss in the cord size of 28 per cent., and yielded, counting 
the value of the tan bark, an increase of |1.53. 

5th. Even 4 to 5 inches thick saplings yielded, when 
barked, an advance of $1.08 when compared with un- 
barked. 

6th. Sixte'en hemlock trunks, 14 to 36 feet in length, 
and 3 to 6 feet in thickness, between 50 and 60 years of 
age, were peeled; they yielded, counting the value of the 
tan barfe^ an advance of 27 cents. The day's work wdll 
yield, according to this calculation, of greater profit. 



METHODS OF ESTIMATING THE TANNING POWERS. 123 



CHAPTER XIV. 

MiJTHODS OF ESTIMATING THE TANNING POWER OF 
ASTRINGENT SUBSTANCES. 

EXAMINATION OP BARKS— CHEMICAL EXAMINATION — R. WARRING- 
TON'S PROCESS — DAVY'S PROCESS — BELL STEPHENS'S PROCESS — MUL- 
LER'S PROCESS — TANNIN CONTAINED IN THE PRINCIPAL ASTRINGENT 
MATTERS — RESPECTIVE QUANTITIES OP TANNING SUBSTANCES NECES- 
SARY TO TAN AN EQUAL QUANTITY OP LEATHER — MODE OF ASCER- 
TAINING THE RICHNESS IN TANNIN OR VALUE OP BARKS, 

The mtans of ascertaining the value of barks are of two 
kinds : 1st. By inspection of the bark. 2d. By chemical 
analysis. This last method is the best and surest. 

EXAMINATION OF BARKS. 

A good bark is known by its color. The most highly 
esteemed is that which is white outside and reddish in- 
side, rough and dry on the side of the wood, breaks easily 
and gives less ligneous matter; the taste is the most 
astringent with a strong smell principally when ground. 
A sign of bad quality is when the epidermis and cortex 
are very thick and have a blackish color; then the bark 
is too old and has experienced a beginning of decomposi- 
tion. It is the same with that which has been left exposed 
a long time to the rain. The bark which is red inside 
has lost its odor, and that which is dirty has lost a part 
of its property. 

chemical EXAMINATION. 

AVe have said that barks contained tannin, gallic acid, 
extractive, etc., and that they were more valuable for 
tanning in proportion as they contain more tannin. It is 



124 CHEMISTRY OF TANNING. 

evident then that by chemically isolating this principle, 
and determining the proportions we could ascertain the 
value of a bark. One of the characteristics of the tannin 
is to form with gelatine an insoluble compound. It is 
then sufficient to ascertain the value of a bark to take the 
amount in weight of the precipitate obtained of equal 
weights of these substances put in infusion into water, 
and precipitate by gelatine. These precipitates filtered 
and dried give by their weights the proportion of tannin. 
We give below the different processes : — 

R. Warrington's process. 

This chemist speaks thus :* " Having ofter^ occasion 
to examine the value of astringent substances used by 
tanners, I think it will be interesting for the trade 
to know my method of operating. 

" I have chosen gelatine as the basis of the determina- 
tion of the value of astringent substances, and after 
many trials with several kinds of gelatine, I have found 
that isinglass of the best quality was the most proper 
for those assays. It is with isinglass that I prepared 
the proof liquor of a quantity such that each division of 
a graduated tube is equivalent to gramme 001 of 
pure tannin. A given weight of the substance was 
treated by water, and the clear liquor was precipitated 
by the proof liquor till no more precipitation was formed. 

" It is necessary during the operation to try from 
time to time a portion of the solution to be sure of the 
progress of the analysis. This operation, on account of 
the nature of the precipitate, has presented some diffi- 
culties. It was impossible to filter ; then I adopted the 
following plan : — 

* Memoirs of the London Chemical Society. 



METHODS OF ESTIMATING THE TANNING POWERS. 125 

" I took a glass fube about 1 foot long and J an inch 
in diameter and introduced into it a little piece of a damp 
sponge that I fixed loosely at the inside end. When I 
desire to extract a portion of the liquor submitted to the 
proof for a particular essay, I immerse a few seconds 
this tube in the precipitated solution. The clear liquor 
filters by ascension through the sponge in the tube, and 
is decanted into another glass; if by adding a drop of 
the solution of gelatine a precipitate is produced, I pour 
back the liquor, and continue the operation till the satu- 
ration is complete. The numbers of degrees of the grad- 
uate glass indicate the quantity of tannin contained in 
the liquor." 

davy's process. 

Take one ounce of the bark to dry, and reduce it to a 
fine powder, digest it in a pint of boiling water, stirring 
frequently; after 24 hours filter through a cloth. Also 
dissolve one drachm of isinglass in one pint of warm 
water, mix equal quantifies of these two liquors, and 
filter; the precipitate is dried and weighed. The difier- 
ence of weights indicates the degree of tannin ; the pre- 
cipitate formed of tannin and gelatine generally contains 
40 per cent, of tannin. 

bell Stephens' process. 

Stephens, while studying Davy's process, has given 
another less imperfect. Mr. Bostwick has ascertained 
that the precipitate obtained by the gelatine stays in 
great part in suspension in the liquor, and is not separa- 
ted by the filter ; in the second place, the proportion of 
gelatine is not constant. This chemist has ascertained 
that the first portions of gelatine give a precipitate which 
contains 50 per cent, of tannin, while at the end it 



126 CHEMISTRY OF TANNING. 

contains very little. Stephens proposes the following 
method : Dip for a few hours, in a weak solution of tan- 
ning matter made with water at 90°, thin skins which 
in 7 or 8 hours extract all the tannin. The increase in 
weight of the skin indicates the quantity of tannin. As 
dry skin badly absorbs tannin, it is better before using it 
to soak it for ten minutes in water at 90° so to render 
it soft in all its parts. The skin ought to be weighed 
when dried before and after the treatment. 

The process of Davy, while subject to the inconveni- 
ences named by Bostwick, is generally followed. That 
of Stephens is good in practice, as it indicates not only 
the strength in tannin, but also the appearance of the 
skin after being tanned. 

muller's process. 

Dr. Muller has established a method for the determi- 
nation of the tannin contained in tanning materials 
which justly deserves the name of technical experiment; 
very satisfactory results are gained by it in a short time. 

The experiment is based upon the property possessed 
by tannic acid of forming with animal gluten a combi- 
nation which is almost entirely insoluble in water and 
which is called tanat (leather). It is therefore neces- 
sary above all to ascertain how much of a solution of 
gluten, which is always prepared alike, is necessary to 
convert a fixed quantity of tannic acid into tanat. 
After ascertaining this proportion we have to find, further, 
how much gluten is necessary to completely precipitate 
the tannic acid in a given tanning material, and from 
these two proportions we have a ratio of which x repre- 
sents the quantity of tanning material to be found. By 
means of a second proportion we can very easily learn 
the percentage of tannin in tanning materials — 



METHODS OF ESTIMATING THE TANNING POWERS. 127 

Working out of this experiment according to Milller. — 
4.38 grains of gluten* are to be dissolved in 140.1 grammes 
of water, and 1.09 gr. of burnt alum added to the solution; 
this addition of alum effects the separation of the tannin 
from the gluten in a much shorter space of time than in 
any other way. With the solution of gluten thus pre- 
pared, the proportions above named are to be fixed : 
a, the weighed part of the pure tannic acid is changed 
into tanat by h, the weighed part of the solution of gluten. 
Now let c be the weighed part of the tanning material, 
on which boiling water is poured and allowed to boil for 
a time, when the water will turn to a very deep brown 
color. Then let it be carefully poured off from the tan- 
ning material into a glass vessel. Upon the boiled tan- 
ning material water .should be poured a second time and 
allowed to boil, and the extract then poured into the 
liquor produced by the first boiling ; and this boiling 
and adding should be continued as long as the tanning 
material gives any solution; that is, as long as tannic acjd 
is produced, which can be ascertained by the brown 
color of the boiling water. When the water remains 
colorless after long boiling, then the dyestuff of the tan- 
nic material may be known to be exhausted, and the 
residuum, the boiled-out substance, together with the 
water still covering it, is to be poured into the solution 
of tannic acid already obtained and added to the gluten 
after it is quite cold. 

Suppose, for instance, h' to be the weighed part of 

gluten necessary to decompose all the tannic acid, then 

we have h ; h' = a: x or h' : h = x : a according as h is 

a b' 
larger or smaller than b'; but in both cases x = — r- = 

* This substance is without doubt gelatine. 



128 CHEMISTRY OF TANNING. 

to the quantity of tannic acid contained in c weighed part 

a b' 
of the tanning material; and, therefore by c; 100 ^= — j-, 

(xf — x' = — P , which is the percentage of tannic acid 

contained in two weighed parts of tanning material. The 
quantity of the consumed gluten will be fixed by weight. 
Fill a glass goblet with the solution of gluten and equi- 
poise it on a scale, and add to the solution so weighed, 
the solution of tannic acid, as long as tannic acid remains, 
then put the glass which still contains some solution of 
gluten, upon the scale again, and it will be lighter than 
before the fixing; the additional weight beyond the 
equilibrium will give the amount of gluten consumed. 

In order to fix this point completely, pour some solu- 
tion of gluten and pure tannic acid, dissolved in water, 
into watch-glasses standing upon glazed paper. With 
two different splints dip a drop of the clear fluid above 
the separated tannic acid, either into the solution of gluten 
or the solution of tannin in the watch-glass; the smallest 
quantity of s^oVo" ^^ unprecipitated tannic acid or surplus 
gluten will appear in the glass in the form of a white 
speck, tanat, which comes up at the spot where dipped. 

This experiment may be made more accurately and 
conveniently by estimating the quantity of gluten, not 
according to weight but by its volume as I have tried it. 
Weighing is liable to error, and it is not so accurate a 
plan as measurement. A vial of the capacity of 70 
cubic centimetres (centimetre is jW of an inch) answers 
perfectly as a measure ; with it we can calculate up to 
0.5 centimetre, and regulate the addition of the gluten, 
even by drops — but it soon became evident that this 
solution of gluten was much too thick for this vial, as 
the narrow mouth of the vial soon became stopped up. 



METHODS OF ESTIMATING THE TANNING POWERS. 129 

and owing to this hindrance in the work, a thick solu- 
tion of gluten does not precipitate tannic acid nearly 
as rapidly as a thinner .and more freely flowing solution. 
I therefore prepared a solution in the following manner: 
I dissolved 2i grains of gluten in 125 centimetres of water 
in which 0.75 gr. of alum had been previously dis- 
solved. When the alum is put in the rough into the 
solution of gluten it dissolves very slowly. 

Disposition of a quart of gluten: 0.71221 grain of 
chemically pure tannic acid was dried for such a length 
of time until its weight remained permanently at 0.6335; 
then this quantity was dissolved in 100 c. c. of distilled 
water; of this solution 4 analyses always of 5 c. c. in 
goblet glasses, and precipitated with solution of gluten 
prepared in the manner above laid down, required as 
follows: 5 c. c. tannic acid; 3.8 c. c. of gluten; 5 c. c. 
ditto; 4.1 c. c. do.; 5 c. c. do.; 4.1 do.; 5 c. c. ; 3.5 c. c. 
do.; 3 minutes were required to clarify the liquid. If 
we take the mean of these results, it will appear that 5 
c. c. =0.031675 grain of tannic acid, require 3.9 c. c. 
of gluten in order to become converted into tanat. 1 c. 
c. of gluten corresponds therefore to 0.031675; 3.9 = 
0.00812 grain of tannic acid. 

By means of these data I have calculated the following 
tables, which will be found very serviceable in working 
out, as they render all calculations unnecessary. 1 c. c. 
of gluten corresponds to 0.00812 grain tannic acid, 
therefore 2 c. c. =0.01624, and so on ; the quantity of 
tannic acid required for any quantity of gluten may be 
rapidly ascertained by multiplying 0.00812 by the num- 
ber of c. c. Example : 4 grains of tanning material would 
require 75 c. c. of solution of gluten, therefore 4 grains 
of tanning material contain 0.609 of tannin, for 75 c. c. 
9 



130 CHEMISTRY OF TANNING. 

corresponds to 0.609 of tannin. In order to reach the 
percentage, the following proportion- must be made: — 

4 : 100=0.609 vx 

x='^=1^.22b per cent. 

If, in each experiment, 4 grains of tanning material 
are employed, the per cent, contents may be easily ascer- 
tained by the following calculation. Gluten contained 
in 1 c. c. amounts to 0.203 per cent., in 2 c. c. to 0.406 
and so on, multiplying the amount consumed in 1 c. c. 
by the number representing the accumulation of centi- 
metres. With careful execution, this method gives re- 
sults which are accurate even to 0.3, 0.5 per cent, as 
my experiments have established. 

Special determination of Aleppo gall-nuts o/1839. 

Is^ determination : 3.6386 gr. of matter required 75 c. 
c. of gluten, being equal to 0.6090 of tannin, therefore 
it contains 16.73 per cent, of tannin. 

2d determination: 4.026 of the same substance re- 
quired 84.4 c. c. of gluten, being equal to 0.685328 of tan- 
nin, therefore it contains 17.04 per cent.; the difference 
amounts to 0.31. 

Mar morina gall-nuts {old). — 1st determination: 3.25675 
gr. required 75 c. c. of gluten, being equal to 0.609 of 
tannin =18. 8 9 per cent. 

2d determination: 3.9186 of substance required 95 c. 
c. of gluten, being equal to 0.77148 of tannin, or 19.60 
per cent. 

Chinese gall-nuts. — 1st determination: 2.1875 gr. of 
substance required 62 c. c. of gluten = 0.486388 of 
tannin =22.23 per cent. 

2d determination: 1.6555 of substance required 46 c. 
c. of gluten=0.37352=22.55 per cent. 

From the above examples the accuracy of my as- 



METHODS OF ESTIMATING THE TANNING POWERS. 131 

sertions regarding the correctness of the results may be 
seen. 0.5, 0.3 per cent, is the error. 

METHOD OF DR. D. W. GERLAND. 

We extract from the London Chemical Neivs the 
following process, which we think very reliable. The 
importance of a sure and an easy method for the esti- 
mation of tannic acid as a means of determining the value 
of tanning materials, has been duly noticed, and a great 
number of processes described for that purpose. An 
examination of these methods, induced by numerous 
samples sent to me for analysis, has convinced me that 
those recommended fail in answering the desired end, 
as some yield too high a percentage of tannic acid by the 
. accompanying gallic acid being estimated as tannic acid, 
some giving altogether incorrect results, while others are 
too complicated to be of service to any but the skilled 
chemist. 

After a long experience I have found that the estima- 
tion of tannic acid is accomplished with great accuracy 
and speed, as tannate of antimony precipitated by a 
standard solution of tartar of antimony, if the operation 
is conducted in the following manner : — 

The solution of tartar emetic I prefer of such strength 
that 1 c. c. will precipitate 0.005 gramme tannic acid. 
One equivalent of tartar emetic dried at 212°, 

= KO,Sb03,C8HAo = 332.2 
requires three equivalents of tannic acid, 

3(C,,H30J = 636 
to form one equivalent of tannate of antimony — 
Sb03,8(CAOJ = t89. 

Accordingly, 0.002611 gramme of tartar emetic will 
precipitate 0.005 of tannic acid of galls, and, therefore, 



132 CHEMISTRY OF TANNING. 

2.611 grammes tartar emetic dried at 212° are dissolved 
in 1000 c. c. of water, each c. c. of which solution is 
then equal to 0.005 gramme of tannic acid. This 
liquor added to a dilute solution of tannic acid produces 
no change, but if a solution of chloride of ammonium is 
mixed with the latter, the tannate of antimony appears 
as a thick, curdy precipitate, which, after stirring, set- 
tles readily, leaving the supernatant solution perfectly 
clear, so that it is easy to perceive whether another drop 
of the antimonial liquor will again cause a precipitate. 
Its voluminous and opaque character makes it very per- 
ceptible to the last, so that I found less difficulty in ob- 
serving the end of this reaction, than with the usual 
estimation of sulphuric acid by a standard solution of 
chloride of barium. If as much and no more of the tar- 
tar solution has been added as will cause a precipitate in 
the sample, the filtrate of the same will be found free 
from both antimony and tannic acid, and the precipitate, 
after filtering, washing, and drying at 212°, consists of 
pure tannate of antimony represented by — 

Sb03,3(C,3H,OJ, 
and contains all the tannic acid of the original liquor. 
Any gallic acid that might have been present in the tan- 
nic acid is •not precipitated under these circumstances, 
and consequently d6es not interfere with the estimation 
of tannic acid; for the ammonia salt, whilst it renders 
the tannate of antimony insoluble, keeps the gallic acid 
in solution. Nor do the coloring matter and other im- 
purities, extracted by water from the tanning materials, 
afiect this process. It is, however, to be observed that 
the reaction of the liquor is neutral or slightly acid. 
The number of c. c. of the standard solution used will, 
therefore, when multiplied by 0.005, give *the exact 



METHODS OF ESTIMATING THE TANNING POWERS. 133 

amount of tannic acid in the sample, or the percentage, 
if 0.5 gramme were employed. 

To illustrate the exactness of the method I add a few 
of my experiments. No. 1. 0.5 gramme of commercial 
tannic acid of galls was dissolved in 100 c. c. of water, 
of which 30 c. c. were mixed with a solution of chloride 
of ammonium and diluted with water to about 200 c. c. 
After having added 29.1 c. c. of the standard solution, 
the filtered liquor was free from tannic acid, showed a 
slight reaction of antimony, and contained gallic acid. 
The precipitate thrown on a weighed filter, and after 
washing with water and dried, weighed 0.1791, and was 
found to contain 18.01 per cent, of oxide of antimony; 
the formula — 

Sb03,3(C,3H30J 

requires 18.13 per cent. The sample, therefore, contained, 
according to the quantity of standard solution used, 97 
per cent, of tannic acid ; calculated from the amount of 
precipitated tannate of antimony, 96.24 per cent, of tan- 
nic acid. 

No. 2. 10 grammes of oak bark are exhausted with hot 
water, the filtered solution diluted to 300 c. c, of which 
50 c. c. were treated as above. The amount of standard 
solution used was 12.51 c. c. ; the weight of the dried 
precipitate was 0.1563 gramme, containing, according to 
calculation, 0.1257 gramme of tannic acid. The oxide 
of antimony in the precipitate was equal to 18.07 per cent. 

No. 3. Dried valonia extract was treated in the same 
manner. 0.5 gramme required 38.8 c. c. of antimonial 
solution; the percentage of tannic acid was 38.92 

It would be an interesting experiment to try the 
tanning strength of barks of different kinds and varieties 
of every country during the four seasons of the year at 
different ages; and it would be more interesting to 



184 



CHEMISTRY OF TANNING. 



analyze at the same time the roots, trunks, branches, 
leaves, etc. 

We give below a table of the quantities of tannin 
contained in the principal tanning substances. 



Sulbstances. 


Percentage of Tannin. Authority. 


Catechu, Bombay . 


55.00 


Davy. 


Bengal . 


44.00 


(( 


" Bombay, light color . 


26.32 


Mulligan. 


" Pegu, dark brown 






color 


46.88 


tt 


Rhatany root . 


42.60' 


Peschier. 


le 


38.30 


C. G. Gmelin. 


Kino .... 


. 15.00 


Vauquelin. 


Butea gum 


18.20 


E. Solly. 


Nutgalls, Aleppo 


65.00 


Guibourt. 


" Chinese 


. 69.00 


Bley. 


•' Istrian 


. 24.00 


Roder. 


Oak, old white, inner bark 


. 21.00 


Cadet de Gassincourt. 


IC <( It tt It 


14.20 


Davy. 


" young " " " . 


15.20 


tt 


" " colored or middle 






bark . 


4.00 


tt 


" " entire bark 


6.00 


Davy & Geiger. 


" " spring-cut bark 


22.00 


Davy. 


" Kermes, bark of the root . 


8.90 


(( 


" 100 years old . 


8.45 


G. Muller. 


" young 


13.81 


tt 


" British, 50 years old 


8.90 


Mulligan & Downing. 


" " about 50 years 


9.16 


(1 (( 


it tt tt ItA 


6.12 


it tt 


" Southampton, about 50 


. 8.80 


tt tt 


" Coppice . 


12.55 


tt tt 


" Irish, 45 years old 




9.50 


tt tt 


" Belgian, popering 




8.33 


tt tt 


" " heavy . 




. 10.14 


tt n 


light . 




. 8.52 


(( (( 


" Bschurgh 




19.35 


G. Muller. 


Divi divi 




29.80 


Mulligan & Downing. 


(( 




. 49.25 


G. Muller. 


Valonia, Smyrna . 




. 34.18 


Mulligan & Downing. 



METHODS OF ESTIMATING THE TANNING POWERS. 135 



Myrobalans 


. 


20.91 


Mulligaii 


I & Downing. 


Mimosa bark .... 


17.87 


ti 


<( 


(( 


31.16 




G. Muller. 


Terra Japonica 


44.00 




Esenbeik. 


Avens root .... 


41.00 




Tr.omsdorfif. 


Squill, bulb 


. 


24.00 




Vogel. 


Statice . 




12.40 




Parrish. 


Birch bark 




1.60 




Davy. 


11 




1.40 




Biggers. 


Beech bark 




2.00 




Davy. 


Larch " 




1.60 




11 


<( (( 




35.10 


Mulligan & Downing. 


Caratree bark 


12.16 


(< 


<< 


Hemlock " . 


18.92 


<( 


tt 


Hazel " . 


3.00 




Davy. 


Chestnut, American rose 


8.00 


Cadet d 


e Gassincourt. 


" Carolina . 


6.00 




(1 


French . 


4.00 


J. 


de Fontenelle. 


" Spanish, white inner 








bark 


1.30 




Davy. 


" Spanish, colored bart 


: 0.30 




ti 


" entire " 


0.50 




It 


" horse 


2.00 


J. 


de Fontenelle. 


Poplar, Lombardy . 


3.50 




tc 


Black thorn . . . 


3.30 




Davy. 


Ash bark 


3.30 




(( 


Sassafras 


. 58.00 




Reinsch. 


Elm . . . 


. 2.90 




Davy. 


Sumach, Sicily 


. 16.20 




(< 


" Malaga 


. 16.40 




(( 


11 ti 


. 10.40 




Franck. 


" Carolina . 


. 5.00 


Cadet de Gassincourt. 


" Virginia . 


. 10.00 




<( 


(( 


. 19.35 




G. Muller. 


" Palermo . 


. 24.37 


Mullig 


an & Downing. 


Willow, Leicester, white innei 








bark 


. 16.00 




Davy 


" colored, middle bark 


. 3.10 




(( 


" entire bark 


. 6.80 




11 


tl . n 


. 3.95 


Mulligan & Downing 


" ' h'dvl 


. of the trunk 


L40 




Biggers 



136 



CHEMISTRY OF TANNING. 



Willow, weeping 




16.00 


Cadet -de Gassincourt. 


Sycamore bark 




. 16.00 


(( 


li 




1.40 


Biggers. 


Eder. . 




. 2.30 


Davy 


Plum tree 




1.60 


Biggers 


Cherry tree 




24.00 


Cadet de Gassincourt 


" Cornish , 




19.00 




Torraentil root 




46.00 




Cornus sanguinea of Canada 


44.00 




Alder bark 


. 


36.00 




Apricot bark . 


, 


32.00 




Pomegranate bark . 


. 


32.00 




Bohemian olive 


. 


14.00 




Tan shrub with myrtle 


leaves 


13.00 




Service tree bark 


. 


18.00 




Cloves . 


. 


. 15.00 


Davy 


Winter bark . 


. 


9.00 


Henry 



Comparative Quantities of Different Tanning Substances 

Necessary to tan an Equal Quantity of Leather, 

Davy, who made a series of experiments of the highest 

interest, ascertained that Catechu is the most energetic 

substance for tanning. According to this chemist one 

pound of Catechu is equivalent to 

Nutgalk 2| lbs. 

3 " 



Sumach 
Willow hark 
Oak . 

Horse-chestnut , 
Elm . 
Ordinary willow 



' 9. 



11 

18 
21 



In treating of extracts, we shall indicate the proper- 
ties of a new preparation of oak bark which unites all 
the properties both of oak and catechu. 



TAN, OR POWDERED OAK BARKS. 137 



CHAPTER XV. 

TAN, OR POWDERED OAK-BARK. 

The more finely divided a substance, the sooner and 
more readily does it yield to the action of the liquid 
which dissolves its constituents. Water, accordingly, 
dissolves the tannin from bark in powder much more 
readily than from bark in coarse pieces. The grinding 
of the bark for tanning purposes is, therefore, indis- 
pensable. It must not, however, be reduced to impal- 
pable fineness, else the solvent will act upon it too 
rapidly. Very fine powders also form a compact mass 
when wet, and thus obstruct or retard the infiltration 
of the solvent liquid. 

Bark is ground in mills varying in construction in 
different countries, and driven or propelled by horse, 
water, or steam power. In England, it is crushed be- 
tween chasers, or stones. There is a mill of ingenious 
construction used in Salleron's tannery in France, but as 
its rapid motion so modifies the bark as to cause it to 
impart color to the hides, we omit a description of it. 

In the South of France they use a vertical mill of 
hard stone, similar to that employed for crushing oil 
seeds. It consists of two vertical stones (Fig. 2), of 
about Ts feet in diameter, and 18 inches in thickness. 
The axle of these stones is fixed in a frame which in- 
closes an upright shaft turning upon a pivot, and fixed 
in the centre of a strong stone bed. Rotary motion 
being communicated, imparts to each stone a double 
movement ; that upon the other, and that which it under- 



138 



CHEMISTRY OF TANNING. 



goes in describing a circle upon the stone bed upon which 
it rolls. 

Fig. 2. 




The axle of each stone should be so adjusted as to 
allow it to be raised or lowered according to circumstan- 
ces. One of the stones is placed nearer to the vertical 
shaft than the other, so as to give a greater extent of 
crushing surface beneath. Two followers press the bark 
forward under the stones, and a cloth is attached to the 
outer one, for the purpose of rubbing off any pieces of 
bark that may adhere to the edges of the stones. 

BagnaUs Machine for Chopping Bark and Fleshing 
Hides. — Fig. 3. General plan of the mill. 

Fig. 4. Longitudinal section, showing the elevation 
of a part of the machinery. 

Fig. 5. Section across part of the mill. 

A (Fig. 3). Part of an undershot wheel moving the 
machinery, b. Shaft of the wheel, giving motion to the 
bevelled cog-wheel c. Another wheel f, placed upon a 
vertical shaft, is made to revolve by the motion of the 
wheel c, and the cogs upon its periphery move the ham- 



TAN, OR POWDERED OAK BARKS. 



139 



mer for beating the bark, and also the choppers, in the 
second story of the building. 



mn 



Fig. 3. 



1 



^ i^iiM^igMfiirMMl%^^WiMfg^a?%:§oPi^^^ 




ig^■^^lL^'^^^^^l^^^^^^l^^^i^l^^^K^^^ i ^H^l^!.^^"s»Elsa^l$l^l^^^^^^ 



D (Fig. 4). A horizontal wheel bevelled upon its inclined 
surface, and toothed in an epicycloidal manner upon its 

Fig. 4. 




periphery. This wheel turns upon the upper part of 
the large horizontal shaft E, which passes through the 
first floor of the building, f. Cog-wheel, before referred 
to, gearing with the large bevelled wheel c. 

G. Pinion upon the axle of the millstone i (Fig, 5). 

p. The beam or handle of the cutting-blades, moving 
upon a pivot, and made to rise or fall, by the motion 



140 



CHEMISTRY OF TANNING. 



communicated to the lever N, by the cogs upon the 
wheel c. When one of the cogs becomes disengaged 
from the end of the lever, the beam falls by its own 
weight, and the steel blades upon its extremity come in 
contact with and divide the pieces of bark placed 
between them and similar knives fastened to the plat- 
form at i. The platform i is made of strong timbers 
firmly secured by bolts to the rafters of the floor, so as 
to enable it to resist the shock of the falling beam. The 
intervals between the knife-blades are open, so that the 
divided pieces of bark may fall through them into a con- 



Fig. 5. 




duit Q, from which they enter the hopper of the mill h, 
to be conducted to the latter by a guide J (Fig. 6). The 
lower part of the conduit Q is provided with a wire-cloth, 



TAN, OR POWDERED OAK BARKS. 141 

which allows the powder to fall into a box k. The tan, 
ground in the mill, passes through the conduit o, and 
falls upon the sieve or bolter l, its finer particles passing 
through into the trough M ; those which have not been 
sufficiently exposed to trituration being received upon 
the concave mortar or support S, and there reduced to a 
state of fine division, by the action of the round-headed 
hammer r, which is worked by the cogs upon the w^heel c. 
The support is hollowed out in such a way that, at each 
blow of* the hammer, the particles of tan acted upon are 
thrown out upon the side opposite to that at which they 
entered it. 

T. Bevelled pinion, in gear with the upper surface of 
the wheel d, and having the end of its shaft connected 
with the crank v, by means of which the motion is com- 
municated to the machinery for fleshing the skins. The 
crank is connected by means of the rod w with the lever 
X, the end of which is perforated with a number of holes, 
by which the bar is so adjusted that the length of the 
stroke may be increased or diminished. 

y (Fig. 3). Shaft moving upon two axles, the sockets of 
which are imbedded in the opposite walls of the room; the 
lever y (Fig. 4) is connected with it near one end ; and at 
about two-thirds of its length the cranks n, n, are attached, 
which give a reciprocating movement to the branches h, h, 
which support the fleshing-knives ; so that, at each revo- 
lution of the crank v, to admit the movement of which 
there is an opening in the ceiling above it, the branches 
A, h, for fleshing the skins, are made to move in a trans- 
verse direction. In Fig. 4, the knife for fleshing is repre- 
sented at/, fixed between two springs a, a, which render 
it sufficiently movable to prevent it from injuring the 
skins when passing across them. It is fastened by its 



142 CHEMISTRY OF TANNING. 

forked extremity to the branch /^ by a screw and nut, so 
that it can be unscrewed and sharpened when necessary. 

z. Stop on the branch h, which is connected with the 
forked lever e, by means of which the knife is made to 
return to the end of the skin without touching its surface. 
The extremity of the branch h rolls upon the roller I. 
By lowering the handle m, the knife is elevated, while 
the skin is being placed upon or removed from the table. 
6. Table or bench upon which the skins are deposited. 
Each table is provided with four wheels p, p, running in 
the grooves g, g, which maintain it in position, and 
enable it to be moved at will by the levers c, c, so that 
each portion of skin may be in turn subjected to the 
action of the knife. 

d. A spring, pressing upon the skin near the edge of 
the table, so as to prevent it from changing its position 
under the fleshing-knife. The iron support, or handle of 
the knife, is forked or divided, so as to receive the blade 
between its two extremities. The knife is 12 or 13 
inches in length, and from 3 to 5 inches in breadth, and 
is adjusted in the open part of the handle, being pre- 
vented from swerving by the two springs a, a. 

The roller /, with its forked lever, should be so ar- 
ranged that the knife can be elevated to the proper dis- 
tance from the table, by pulling the handle m, and hook- 
ing it upon a nail, so that the skin may be removed or 
placed upon the table without the necessity of ungearing 
the pinion t; the work being again commenced when the 
handle is allowed to rise. 

Two benches or tables are used in this apparatus, in 
order that the knife may be in operation above one of 
them, while the workman is occupied in adjusting a fresh 
skin upon the other. These benches should be as wide 
as the largest skins, and should be made sloping at a 



TAN, OR POWDERED OAK BARKS. 



143 



slight angle. The skins are kept in close contact with 
the surface of the support, by clamps pressing their bor- 
ders down upon its edges. The pressure of the knives 
upon the skin is regulated by weights placed upon the 
beams or branches which support them. The inventor 
does not confine the application of this portion of the 
machinery to the preparation of skins for the tanning 
process ; but also adapts it to the purposes of tawing and 
to those of the currier, by substituting hard brushes or 
other implements for the knives. Motion may be com- 
municated to the machinery by the water-wheel already 
described, by a steam-engine, or by horse power; the 
labor of two horses being sufficient for the purpose. 

Weldoris Mill for Grinding Oak-Bark. — Fig. 6, A. 
Wooden beam or cross-piece, imbedded in the walls of 

Fig. 6. 




the building, and perforated for the reception of the 
upper axle of the main shaft. 

B. Iron plate or socket for the axle. 

c. Axle of the shaft, the dotted lines showing its con- 
nection with the latter. 



144 CHEMISTRY OF TANNING. 

D. The shaft, which may be square, octagonal, or of 
other suitable form. 

E. Lever giving motion to the shaft by the power of 
horses harnessed to the end. When water or other 
power is employed, the lever is replaced by a wheel 
with the proper gearing. 

F. Cylinder forming the lower part of the mill. It 
should be made of iron or brass, and may be either com- 
pact or hollow, as shown by the dotted lines in the figure. 

G. Teeth, or projections for breaking and grinding the 
bark. 

H. Lower teeth for the same purpose. 

I. External iron or brass cylinder, provided with simi- 
lar projections upon its inner surface, and firmly clamped 
and bolted to the solid framework Q, which forms the 
base of the machine. 

K. Lower pivot or axle, firmly united with the main 
shaft, and turning in a socket like the upper one. 

L. Iron or copper socket, fixed in the cross-beam R. 

M. Regulating screw passing through the nut N, and 
the lower cross-beam t. By turning it, the teeth within 
the mill may be made to approach or recede from each 
other, so as to effect, at will, a coarser or finer division 
of the bark. 

0. Hopper, made of strong wood for receiving the ma- 
terials which are to be ground. 

p. Conical lining of the interior of the mill, also made 
of strong wood. The whole apparatus is supported upon 
four uprights, Q, Q, firmly imbedded in the ground, and 
held together by the cross-beams R and T, there being 
two at R, meeting each other at right angles. Sieves of 
wire are placed between the cylinder F and the floor, 
which permit the passage through their interstices of 
the fine tan, and retain that which is too coarse. 



TAN, OR POWDERED BARKS. 



145 



Since its first introduction, Mr. Weldon has improved 
the construction of his mill, by making the teeth mova- 
ble, and by other changes which we proceed to describe. 

Fig. 7. Section of the improved mill. 




A, A. Hopper for receiving the bark. 

B. Shaft of the mill. 

c. Conical casing of the cutting surfaces, for feeding 
the mill. 

D, D. Collar for staying the teeth, with four bolts, h. 

E. Elevation of the conical part of the mill in which 
the teeth are placed. 

G. Section of the opposite side, showing the manner 
in which the teeth are adjusted. 

d, d. One of the teeth entering the lower neck. 

H, H. Lower collar in which the teeth are imbedded. 

a, a, a. Outer cylinder, or cone, cast in one piece, and 
showing the manner in which the movable teeth f, r, 
are adjusted. 
10 



146 CHEMISTRY OF TANNING. • 

I, I. Rim or collar for the attachment of the movable 
teeth; a part of it is seen detached in Fig. 8. 

K, K. Support of the interior of the mill, fastened to 
the outer cone or cylinder by two bolts, c, c. 

Fig. 8. 





L. Lower part of the shaft, turning in a copper socket 
M, which rests upon the top of a screw by which the 
height of the inner part of the mill is regulated. Fig. 
9 exhibits this part, with the collar of the rim, in which 
the socket and adjusting screw are placed. 

Fig. 10. One of the movable teeth, detached from the 
exterior of the mill. 

Fig. 11 is one of the teeth from 
Fig. 10. IJ IjFig. 11. ^j^g interior of the mill. 

These teeth are blades of iron or 
composition-metal, ground to an edge, and so placed in 
the mill that the cutting surfaces are opposed to each 
other, and inclined in a direction opposite to that of the 
revolution of the shaft. 

Farcofs Bar Jc- Chapping Machine. — This machine con- 
sists of two feeding cylinders A, A. (Fig. 12), which con- 
vey the bark, previously spread out upon an inclined 
table a, to the edges of four large steel blades b b, which 
are fixed in a spiral direction upon the periphery of two 
parallel circles, revolving with the shaft c. The cylin- 
ders A, A, are grooved, and are moved by cog-wheels with 
long teeth. The power, from whatever source, is trans- 
mitted at the same time to these wheels, and to the 



TAN, OR POWDERED BARKS. 147 

bladed circles ; 6 is a steel tie-piece, which supports the 
pieces of bark when exposed to the action of the knives, 

Fiff. 12. 




each of the latter passing over it, like one blade of a 
pair of shears over the other. 

The levers f suspend the weight G, the object of which 
is to bear upon the shaft of the cylinder A, which is con- 
stantly elevated by the passage of the bark beneath it. 
Guides are so placed as to direct these levers, in their 
vertical movements, and the bark is prevented, by guards 
or side pieces, from falling out of the grooves, over the 
sides of the cylinders. The feeding cylinders are 2 feet 
2 inches in circumference, and the relation of the pinion 
of the wheel c to the wheel J which moves it, is that of 
1 to 5. About 56 feet of bark will pass between the 
cylinders in one minute ; in ^the same time the wheel 
makes 130 revolutions, and as it is armed with 4 blades, 
the bark is cut into 520 pieces, each one nearly Ij^Q-th 
inches in length. More than 1600 pounds of bark can 
be chopped in an hour with this machine, when in good 
order and properly worked. Some are made, with which 
one man can work up daily more than 3000 pounds. 



148 CHEMISTRY OF TANNING. 

Fig. 13 is the plan in elevation. 

Fiff. 13. 




Fig. 14 is the ground plan. 

Fig. 14. 




Fig. 15 shows the axle-pin of the bladed cylinder; 
and Fig. 16 is an end view of the latter. 



TAN, OR POWDERED BARKS. 
riff. 15. 



149 



Fiff. 16. 





Fig. 17 represents the cast-iron frame which supports 
the channelled cjlinders and bladed cylinder. 

Fig. lY. 




■ The bark, after being chopped as described above, is 
submitted to the action of the mill, which consists chiefly 
of two parts, the receiving and the revolving cylinder. 
The former is a thin, hollow cylinder, terminated below 
by a truncated cone, the interior of which is provided 
with spiral blades or teeth, some of which extend as far 
as the lower part of the cylinder. The base of the cone 
is attached by legs to the cast framework which supports 
the whole apparatus. Above the cylinder is a hopper, 
which is fed from time to time with chopped bark, the 
powdered tan falling down between the outer cylinder 
and the inner one. The outer surface of the movable 
cylinder is provided with spiral teeth, similar to those of 



150 CHEMISTRY OF TANNING. 

the inner one, find made of a wedge-shape, so as to pre- 
sent a cutting edge to the fragments of bark, which are 
first cut and divided by the teeth which extend towards 
its upper part, and are then pulverized by those upon 
the two conical surfaces. The cylinder is made to re^ 
volve by a shaft set in a socket which is stayed by a 
tie-piece. This latter is traversed by a screw, by means 
of which the nut may be raised or lowered, so as to in- 
crease or diminish the space between it and the receiving 
cylinder, and to alter at will the quality of the powder 
as to fineness of division. A bar passes horizontally 
across the interior of the inner cylinder, and is firmly 
attached to the shaft passing through it. The horse 
moving the machinery is harnessed to an arm attached 
to a cast-iron plate on top of the shaft. This mill is 
calculated to make 25 revolutions in a minute, and is 
capable of grinding 8600 pounds of bark in 24 hours. 

Bourgeois s Bark Mill. — This machine, which was in- 
vented in 1841, and is described in volume liv. page 
193, of the French reports of expired patents, is used to 
grind bark by means of two cylinders, one of which 
(Figs. 18 and 19), serving as a case for the handle, is of 
a cylindrical shape externally, while the other and in- 
ternal one is conical; the mill revolving in a vertical 
instead of a horizontal direction. The outer cylinder 
12 is fixed by an iron framework, 10, to the wooden 
supports of the mill, while the inner cylinder, 11, is 
movable. This cylinder and the inner surface of the 
outer one, are both fluted with longitudinal grooves, de- 
scribing curves along their length. Each of these grooves 
is divided into two, at the larger end of the cylinder, and 
into four at the smaller end, the separation commencing 
at the middle. The inner cylinder can be completely 
encased in the outer one, by the turning of the screws, 



TAN, OR POWDERED BARKS. 



151 



14, and tlie arrangement of grooves is intended to effect 
a more or less complete division of the particles of tan. 
When the cylinders are closely in contact, the bark is 
first exposed to the action of the larger grooves, which 
are deeper than the others, and then becomes engaged in 
the second and third divisions, by means of which it is 
reduced to a fine powder. If it be desired to produce a 
less complete trituration, the screws, 14, are loosened, and 
the spring, 13, then presses the inner cylinder from its 
place, in such a manner that the bark is only acted upon 
by the larger grooves. 

Fig. 18. 




Fig. 18. 1. Hopper of the mill. 

2. Spout of the hopper. 

3. Regulator of the spout. 

4. 5. Escapement wheel. 

6. Handle of the regulator. 



152 



CHEMISTRY OF TANNING. 



7. his, strap attached to the spout. 

8, 9, 10. The spout and its motive appli- 

ances — spring and strap. 

11. Handle for turning the machine. 

12. Arm of the lever turning the spout. 

13. Trundle. 

14. Large cog-wheel. 

15. Small cog-wheel. 

16. Internal conical cylinder. 

17. External conical cylinder. 

18. Trough for receiving the tan. 

19. Wooden fram*ework. 

Fig. 19. 




Fig. 19. 


1. 

2. 
3. 
4. 


Fly-wheel. 

Spout under the hopper. 

Hopper. 

Trundle. 




5. 


Lever arm for turning the spout. 




6. 


Axle of the lever. 




7, 


8, 9. The motor and regulating appli 




10. 


ances of the spout. 
Framework supporting the cylinders. 



TAN, OR POWDERED BARKS. 153 

11. Internal cylinder, with grooves cut as 

before described. 

12. External cylinder channelled like the 

inner one. 

13. Spring, regulating the inner cylinder. 

14. 15. Compressing screws acting upon this 

cylinder. 

16. Spring acting upon the spout. 

17. Escapement wheel. 

18. Eegulator of the spout. 

19. Handle of the regulator. 

20. Axis of the cylinders. 

21. Small canting-wheel. 

22. Large canting-wheel. 

23. Axle of the trundle and fly-wheel. 

24. Crank. 

25. Wooden framework. 

Lespinasses Barh Mill. — This apparatus was invented 
in 1843, and is described in vol. lix. at page 428, of 
the French expired patent reports. Fig. 20, d, iron 
shaft turned by the pinion, moved by the power, and 
supporting and moving the stops of the rammers or 
stampers, c, shown at h in the figure. This shaft acts 
upon the conical pinion e, and through it upon the simi- 
lar vertical pinion /, which communicates the motion to 
a small horizontal shaft, I, upon which there is another 
similar pinion, g, by means of which the horizontal pin- 
ion, Ti, is made to revolve. This latter transmits tha 
motion to a vertical shaft, o, and gives a reciprocating 
movement by means of the pinions, e, /, g, li, to the 
curb, m, placed horizontally between the sides of the 
rammer, n. This curb, by its constant movement to and 
fro, forces the portions of bark divided by the knives of 



154 



CHEMISTRY OF TANNING. 
Fig. 20. 




the rammer, n, through the holes, x, made of different 
dimensions in the sides of the apparatus, into the con- 
duit, t, and the trough, u. Above this latter is a drum, 
z, connected by a strap, 5, to which the buckets, 6, are 
adapted, with a similar drum, z'. These two drums are 
made to revolve by a strap v, moving at one end over a 
drum, 7, placed at the extremity of the shaft, d, and at 
the other, upon another drum, 7', above the preceding, 
and which is connected with that supporting the strap, 
5, with the buckets, so that these latter, in their revo- 
lution, become filled with the tan in the trough, u, and 
empty it into the wooden hopper, 8. 



TAN, OR POWDERED BARKS. 155 

In the bottom of* this hopper is an opening connected 
with a wooden conduit, leading to a sieve, which is di- 
vided lengthwise into three parts, each of which is per- 
forated with holes of different sizes. This sieve is moved 
by an arrangement below it, which is connected with the 
strap, y. 

12. Troughs to recieve the residue from the sieve, 10. 

13. Bags in which the residue of tan is placed. 

14. Cords keeping the bags in place under the mouth 
of the trough. 

15. Lever of the rammers. 

%. Arched framework for keeping the shaft, o, in a 
vertical position. This shaft is divided into two parts, 
connected by means of a coupling, s, which may be sepa- 
rated at will, by means of an iron tool, y, attached to the 
framework of the machine. 

1. Small stops for regulating the movement of the 
rammers. 

2. Cushions through which the arms of the curb pass. 

3. Framework supporting the horizontal shaft, I. 

4. Supports of the drums, over which the buckets 
revolve. 

a. Wooden framework of the machine. 

5. Beam supporting the pegs for keeping the rammers 
at rest. 

c. Rammers with knives at their lower ends. 

16. Cross-bars made to revolve by the shaft, o, so as 
to strike against the wooden box, t, and hasten the de- 
scent of the tan into the trough. 

Wiltsea Mill. — This machine, known as the " Catskill 
Mill," and extensively used in the tanneries of the Uni- 
ted States, is made by A. and B. Wiltse, intelligent and 
enterprising machinists of Catskill, Greene Co., New York. 
It is constructed upon the principle of the shears, the 



156 



CHEMISTRY OF TANNING. 



teeth being arranged with their edges at an angle, and 
thrown forward, so that the bark may be driven in and 
ground rapidly, and passed through without interruption. 
Fig. 21 represents the machine, which may be driven by 

Fig. 21. 




water or steam power, and so arranged as to receive the 
bark from the breaker and to deliver it ground in the 
leach-vats. To give a better idea of the manner in which 
it works, we give, on page 157, a plan showing the rela- 
tive positions of the breaker, bark-mill, and leach-vat. 
Fig. 22 is drawn upon a scale of a quarter of an inch to 
one foot. 

A is the water-wheel, and C its shaft ; B is the bevel- 
wheel which drives the bevel pinion D on the foot of the 
main upright /, which also carries a spur-wheel ^, and 
drives a spur-pinion F on the shaft G. The top of the 
mill sets ten inches below the second floor, in order to 
admit the bark running from the cracker J, K, above. 
This latter consists of a cast-iron curb or hoop J, of 18 
inches diameter, and ten inches depth, with three jagged 
teeth, as shown in end and interior views at/. The top 
of the cracker K is made of two blocks of wood, firmly 
secured to two uprights, represented by the dotted lines, 



TAN, OR POWDERED BARKS. 



157 




158 CHEMISTRY OF TANNING. 

by means of bolts passing through the portion which laps 
tRem. The two blocks of JThave openings in their cen- 
tres, of 18 inches diameter at the base, and 24 inches at 
the top, to correspond with the size of the curb on which 
they rest. About 7 J inches from the bottom are four 
strong wrought-iron teeth, so inserted as to be in the 
centre between the teeth on R, r. tThe latter are secured 
to the shaft /, inside of K, as indicated by dotted lines; 
and S, s, is also similarly placed on shaft L, inside of J,j. 
A second length of the iron shaft L, drives N by the aid 
of the bevel-wheels Mand N, which are so geared as to 
drive, in turn, the pulley-shaft at the head of the ele- 
vators. The elevators take the bark from the mill and 
deliver it into a bark-room or loft above the leach-tubs Q, 
whence it may be drawn, as wanted, through a trap. 

The drawing shows two leach-tubs, but the number may 
be increased according to the demands of the tannery. 

The above mill possesses superior advantages, as it 
does its work effectually and with despatch. It cuts the 
fibre of the bark short, without flouring it, and passes it, 
even when wet, without becoming clogged. It is de- 
signed, also, for purposes of economy and durability, as 
well as of convenience; the arrangements of the parts 
being such, that when any of them, by wear, require re- 
newal, they may be easily removed and replaced by 
others. 

When worked to its utmost capacity, it will grind from 
one to two cords of bark per hour, and must be driven 
at the rate of 150 revolutions per minute by a ten-horse 
engine. At 100 revolutions it is less efficient. With 
one horse power, it may be driven at the rate of five 
revolutions per minute, and will then grind one cord in 
from one to' three hours. The cracker should move at 
the rate of 30 to 40 revolutions per minute. 



TAN, OR POWDERED BARKS. 



159 



If steam is used as the propelling force, the waste 
steam may be economized and applied to heating the 
leach-vats. A convenient arrangement for this purpose 
is constructed by the Messrs. Wiltse. 

Birelys Mill. — Another ingenious grinding apparatus 
is that invented by Mr. Valentine Birely, of Frederick 
County, Maryland. It reduces the bark to shreds and 
strings, forms favorable to the entire extraction of its 
soluble matter by the liquor of the vats. Fig. 23 pre- 



Fig. 23. 




-^ 



sents a perspective view, and Fig. 24 a vertical cross- 
section of the machine. 

The framework is of cast-iron, with apertures at the 
sides for the journals of three cylinders, and flanges and 
ribs for securing a wooden hopper. These cylinders are 
of dijfferent diameters, and are propelled by means of a 
drum and cogs at the ends. Being denticulated on their 
surfaces, and revolving in concaves similarly studded 
with teeth, and arranged in alternate order to correspond 
with the reversed movements of the cylinders, the bark 



160 



CHEMISTRY OF TANNING. 




is reduced with great readiness, and the mill runs with- 
out obstruction. The coarse teeth of the first cylinder 
break it down preparatory to its passage through the 
next and finally the last cylinder, which delivers it 
ground to the required degree of fineness. 

These mills are made of three sizes, and the largest, 
driven by a ten-horse power engine at the rate of 80 
revolutions per minute, will turn out twenty-five cords 
of bark every twelve hours. 

The lengths of the cylinders in the three difierent 
sizes are, respectively, 21, 24, and 33 inches; and the 
smaller ones grind in proportion to the power applied. 



TANNING EXTRACTS. 161 



CHAPTER XVI. 

TANNING EXTEACTS. 

For some years past, tanners have endeavored to ac- 
celerate the tanning process; and this end can be attained 
only by the use of materials very rich in tannin, and in 
small bulk. That is the reason why Gatecliu or terra 
jajQonica is so extensively used now. But many tanners, 
and we think they are right, object to the use of this 
substance, and prefer barks. We have been struck for a 
long time with the fact that no one has yet conceived 
the idea of manufacturing from bark an article having 
all the properties of oak or hemlock, and containing as 
much tannin as catechu. Several improvements have 
been made lately in the manufacture of extracts proper 
for accelerating the tanning process, but those improve- 
ments are not yet complete, for in these extracts a large 
portion of the tannin is destroyed and transformed into ex- 
tractive. Before giving the process for manufacturing an 
extract containing all the tannin in an unaltered state, we 
shall give descriptions of the processes lately introduced. 

J. ConneVs Concentrated Extract. — This extract is thus 
prepared : He makes an inspissated extract of the bark, 
that is, he exhausts it completely by water, then evapo- 
rates it over fire in syrupy consistency, and dries it in 
connection with bark dust. 

This extract has two inconveniences: 1st. A part of 
the tannin, by the action of air and heat, is transformed 
into extractive matter and a brown coloring matter is 
developed. 2d. This extract will not dissolve entirely 
in water. 
11 



162 CHEMISTRY OF TANNING. 

Its only advantage is in being a little richer in tannin 
than the bark employed. 

A. Steers's Process. — We are unacquainted with the 
mode of preparation of this extract; but from what we 
have seen we believe that the process is the same as the 
above. 

According to Mr. Steers the process for reducing the 
tanning properties of the bark to an extract only -^-^ of 
the original bulk of the crude bark offers the following 
advantages : — 

The means of controlling the purchases of hides and 
sales of leather by enabling tanners to choose suitable 
city locations for their tanning operations, as the induce- 
ments of supply and demand may determine. 

The means of securing a certain and permanent sup- 
ply of tanning material at a uniform and unvarying figure 
to conduct their operations, and that figure less than the 
amount now paid by the most remote bush tanners. 

To bush tanners the means of obtaining 25 per cent, 
more tanning material out of the same quantity of bark 
without increasing the cost of extraction. 

To both city and country tanners the facilities of mak- 
ing liquors of any and every desirable amount of strength, 
to the want of which is generally attributed the tanner's 
greatest difficulty in attempting to compete with the 
European tanners in sole-leather. 

To curers of bark and manufacturers of bark extracts 
for tanners' purposes, besides the basis of the proposed 
trade being of the most stable character, and giving to 
those who engage in it an unusual control over the 
subduing and settlement of wild lands, it secures to their 
operation in extract an immense direct profit, clearly 
exhibited and fairly calculated by assuming the difference 



TANNING EXTRACTS. 



163 



of price between the place bark is procured at, and the 
place it is consumed as profits. 

By this process of tanning butts and middlings, the 
hides being prepared in the usual manner and tanned 
with ordinary liquors, the most perfect tanning of the 
heaviest sole-leather is effected within four days, and 
an unusually great gain of weight is obtained, with a 
consequent rendering of the leather almost impervious 
to water, together with a susceptibility of a very improved 
finish. There is also a vast saving of tannic acid, as the 
unavoidable loss by volatility in the common exposure 
of present tanneries is equal to 50 per cent, of the bark 
used therein, as shown by the experiments of chemists 
and the statistics of large American tanneries. 

As we have said above, the author of this book has had 
occasion to examine this extract, and it contains a large 
quantity of extractive matter, a sure sign of destruction 
of tannin. He tried it on a calf-skin, and it required 
two weeks to be completely transformed into leather. 

It is true that the above advantages are exaggerated, 
but, nevertheless, the introduction of this extract is an 
improvement. We shall now describe a process we have 
tried, and which has succeeded with us very well. 

We use the following apparatus : — 

Fig. 25. 




164 CHEMISTRY OF TANNING. 

AAA, ordinary wooden barrels of a capacity of 40 gal- 
lons. The bottom of each barrel is covered with straw. 
Each is filled with the bark we mean to treat, which is 
covered with 20 gallons of water. Leave 24 hours, and 
then introduce the steam by the main pipe CG. Leave 
it to disengage until the barrel is full, then shut the 
cocks BBB and leave 12 hours. Draw the liquor by the 
pipes DDD. All the liquid is introduced into a vacuum 
pan and distilled at a temperature which does not exceed 
120°. Continue to exhaust the bark as above described, 
till the water is nearly colorless, and evaporate all the 
liquors in the vacuum pan. 

When the evaporation is completed the extract is 
drawn off in a jar and left to cool. 

It is easy to ascertain when the evaporation is achieved ; 
for that purpose take out a little of the extract and let 
it cool ; on cooling it will become hard enough to be 
broken with the fingers. 

Such extract has all the properties of the bark reduced 
to a small volume, and the evaporation being made at a 
low temperature without the contact of the air, the 
tannin is unaltered. 

1 Ih. Extract of White-oak bark represents . 6 lbs. of bark. 

1 " 

1 <( < 

1 " 

The above table shows that these extracts are richer 
in tannin than catechu, and have at the same time all 
the properties of the bark employed. We hope to see 
them used in preference to any other. The editor of 
this work has made many experiments on this subject, 
but unhappily they are not achieved and are uncom- 
pleted, but, when terminated, he will publish them, as 
they will be of great interest to practical tanners. 



" Avens root 


ti 




. 4 


" Sumach 


(t 




. 6 


" Divi divi 


(( 




. 4 


" Valonia 


(( 




. 4 


" Hemlock 


tt 




. 4 



SKIN. * 165 



SECTION III. 

SKIN. 
CHAPTER XVII. 

PROXIMATE PEINCIPLES OP LEATHER— STRUCTURE 
OF THE SKIN. 

Proximate Principles of Leather, 

As may be inferred from its nature, leather is formed 
by the combination of the substance of the skin -with 
any other compound which has the property of render- 
ing it imputrescible and elastic. Many substances pos- 
sessing these properties in relation to skins of animals, 
are known to exist both in the organic and inorganic 
classes ; but the one most generally employed as well as 
the most efficient is tannin. That a firm chemical 
union of the two bodies, such as that above referred to, 
exists, is evidenced by the modified form of the material, 
and the physical appearance and chemical behavior of 
leather, when subjected to microscopical and chemical 
examinations. The principle in the skin esteemed by 
the tanner is a gelatino-fibrous compound, which con- 
stitutes the basis of leather ; and the combining agent 
— tannin — partakes of an acid nature, so that by uniting 
with the gelatino-fibrous material the former is, as it 
were, thereby salified, so that it is no longer subject to 
the ready putrefactive change which the skin undergoes 
under the influence of air and moisture. As the gelatino- 
fibrous principle forms only one of several others in the 



166 



CHEMISTRY OF TANNING. 



hide of the animal, so the tannin constitutes only one 
among many other substances in the sources whence it 
is extracted. 

Structure of the SMfi. 

Strictly speaking, the skin of animals is composed of 
two parts, the corium or cutis, and the cuticle or epi- 
dermis ; the former is the portion which enters into the 
composition of leather, and forms the true skin; and 
the latter constitutes the exterior covering in which the 
fur, wool, or hair of the animal is rooted. Some physi- 
ologists, however, distinguish three distinct parts in the 
skin, namely the corium, rete mucosum, and the cuticle. 
These several parts are illustrated in the two following 
figures'. 

Fig. 2t. 




The former, Fig. 26, shows the pdsition of the hair, 
and the latter. Fig. 27, the magnified layers of which the 



SKIN. 167 

skin is composed. In both A represents the epidermis; 
B the rete mucosum in which the roots of the hair are 
imbedded ; C, the fibrous tissue of the true skin ; and 
D, the cellular tissue beneath the latter, showing the fat 
cells, a, in the latter figure, and sweat glands, &, with 
the follicles, /«, through which this secretion passes out 
to the surface of the skin. 

Behavior of the Epidermis and Cutis with Reagents. 

When the fresh skin is immersed and macerated re- 
peatedly in water, the matter of the cuticle is separated 
from the fibrous substance of the cutis, not by the solu- 
tion of the former, but, as it would appear, by dissolving 
an extractive matter amounting, according to WeinhoUs 
analysis, to about 8J per cent., and which is probably, 
to some extent, intermediate between the horny matter 
of the cuticle and the cutis. . Weak acids also abstract 
it, but solutions of the alkalies and of many of their salts 
are more effectual for bringing about the separation, 
since these agents dissolve it. The epidermis, which is 
analogous to horn, does not combine with tannin or any 
other substance, by the agency of which leather is pro- 
duced. Hence it becomes useless to the tanner, and 
therefore the first process to which hides and skins are 
subjected by him, is that for removing the hair and epi- 
dermis, both being useless. 

The corium, deprived of the epidermis, is a substance 
formed of a number of fibres ramifying and intersecting 
one another in every position, leaving, however, inter- 
stices contracting in size as they reach the other portion, 
and which are more or less charged with fluid matter, 
that serves to renew the cuticle, and keep the skin pliant 
and moist. On treating the skin with water these mat- 
ters are removed, and ultimately there remains but the 



168 CHEMISTRY OF TANNING. 

fibrous portion saturated with water. In this state it 
appears semi-transparent, and if the water be expelled 
by a gentle heat, it assumes the physical appearance of 
horn, constituting only about 32 i to 33 per cent, of the 
raw hide. 

From Weinholt's researches, it appears that the skin 
deprived of the epidermis and its subjacent fluid, as also 
of the mucous membrane and fat on the interior, affords 
43 per cent, of solid matter, yielding : — 

Fibrous matter ...... '14.42 

Uncoagidated albumen . . . . .3.49 

Extractive matter insolnble in alcohol . . 17.44 

" " soluble " . . 2.32 

Fatty matter and loss . . . . .2.33 



100.00 

Digestion in water removes the albumen and extrac- 
tive matter taken up by this menstruum ; in alcohol the 
further portion of extract dissolves, and ether sepa- 
rates the fat with which the residue is impregnated. If 
the corium, deprived of the epidermis is treated with 
boiling water, it dissolves with the exception of a little 
fat and some nervous filaments ; and when the liquid is 
evaporated slowly, a gelatinous residue is left, which 
when the entire skin is operated upon forms the glue of 
commerce. 

This efiect of the water does not arise, however, from 
the solution of the gelatine which, as might be supposed, 
the skin contains ; but it modifies the components of the 
fibrous tissue, so as to bring them into this compound. 
The same property is possessed by acid and by alkalies 
in a more powerful degree, since the change is effected 
by these agents at the ordinary temperature. 



CONSTITUTION OF THE SKIN. 169 



CHAPTER XVIII. 

CONSTITUTION OF THE SKIN. 

FIBRIN — GELATINE — ALBUMEN. 

Composition of the Shin. 
Having treated of the structure of the skin we proceed 
naturally to consider its composition. The skin of ani- 
mals consists of filbrin, gelatine, and small portions of 
albumen and fatty matter. The first two form, as it 
were, the basis or network of the whole tissue, a portion 
of which, if boiled with water, yields its gelatine while 
the fibrin remains. The epidermis of the skin does not 
combine with tannin. The properties of these substances 
which play such an important _part in tanning are as 
follows : — 

Fibrin 
Exists in the animal structure as the basis of the muscu- 
lar tissue. It occurs in solution in lymph, chyle, and 
blood, from which it separates by coagulation, as soon 
as these fluids cease to form a part of the living organ- 
isms. It is prepared by carefully whipping blood; it 
separates in elastic, stringy mas'ses, which must be 
washed repeatedly with water to remove coloring mat- 
ter, and digested frequently with alcohol and ether to 
free it from fatty substances. Dry fibrin is an opaque, 
yellowish mass ; if transparent, it indicates the presence 
of some fat. Insoluble in alcohol and ether. Digested for 
a long time in water at 390° it is dissolved with a slight 
decomposition ; it is thrown down from its solution by 



170 CHEMISTRY OF TANNING. 

acids. Its solubility in saline solutions has been tested; 
when saturated it forms clear viscid liquids generally 
coagulable by boiling. When burned it gives the same 
smell as albumen and yields ashes composed of phosphate 
of lime and magnesia. 

In sulphuric and mono or bibasic phosphoric acid it 
becomes gelatinous, and forms a neutral compound solu- 
ble in water. Nitric acid converts it into xantho-jproteic 
acid. When dry it forms a blue solution in strong hy- 
drochloric acid. 

Muscular and venous fibrin both dissolve at a gentle 
heat, in acetate of soda, hydrochlorate of ammonia and 
nitrate of potash, forming solutions coagulable by heat, 
and exhibiting the properties of dissolved albumen ; but 
neither arterial fibrin nor that of the buflfy coat can 
undergo this change. By putrefaction it is transformed 
into a volatile fatty body having the characteristics of 
butyric acid. The same result is produced by heating 
it with potash lime at 320° to 356°. 

Its ultimate percentage composition, according to 
Messrs. Dumas and Cahours, is : — 
Carhon 52.78 
Hydrogen 6.96 

Oxygen 23.48 (with some sulphur and phosphorus) 
Nitrogen 16.78 



100.00 ' 

Its formula is C^oHsiOisN^SPh, or lOPR+SPh. 

Pure fibrin, when added to water acidulated with hy- 
drochloric acid and containing yeast, forms a clear solu- 
tion similar to that of protein, and from which acid and 
alum precipitate a flocculent body. Without yeast a 
temperature of 212° will produce the same effect. By 
evaporation in vacuo it leaves a light yellow residue 



CONSTITUTION OF THE SKIN. 171 

analogous to dry white of egg, soluble in warm water, but 
not coagulable by heat. After separating the dissolved 
part from the acid it has a composition closely approxi- 
mating to cliondrin, but without its chemical properties. 

Gelatine 

Is a solid, transparent, colorless, corneus substance, 
which forms with boiling water a solution that, on cool- 
ing, takes the consistency of ,a jelly. In its natural state 
and as existing in the cellular tissue, bones, tendons, etc., 
to which in their woof it serves to give form, it has the 
name of Tiistose. This latter being treated with boiling 
water and dried, becomes gelatine ; but, previous to this 
action, bears the same relation to the latter, in appear- 
ance and properties, as can exist between a completely 
organized body and its constituent elements in a state 
of complete desiccation. 

Cliondrin is the gelatine of cartilages, and is precipi- 
tated by acids, alum, and salts of lead. Olue is the 
technical term for the gelatine of bones, hoofs, and 
hides, isinglass for that from certain fishes, and size for 
the aqueous extract of parchment scraps and several ani- 
mal membranes. At 212° gelatine softens and melts, but 
at a higher temperature it decomposes into animal pro- 
ducts and a slight residue of earthy matters. In cold 
water it swells up and loses its solidity, but when impreg- 
nated with water, if heated at 140°, it becomes so mi- 
nutely suspended as to give to the liquid the appearance 
of a solution insoluble in alcohol and ether. With 
tannin it forms a very intimate combination, and Miiller 
considers this compound as definitely proportioned. 
Gelatine is transformed by nitric acid into oxalic acid ; 
sulphuric acid transforms it into sugar of gelatine, or 
glycocol, leucin, and sulphate of ammonia. 



172 CHEMISTRY OF TANNING. 

Potash converts it into a mixture of sugar of gelatine 
and leucin, and though not of the protein series, it may, 
nevertheless, contribute to the nutrition of the gelatinous 
tissues. Bichloride of mercury coagulates and renders 
it insoluble, but an excess of gelatine dissolves the mer- 
curial compound. 

By long digestion at 212° gelatine loses its gelatinizing 
power, and forms, on evaporation, a gummy mass, readily 
soluble in cold water. 

The ultimate composition of gelatine is : — 



LowiG. 


Mulder. 


Garlo'n 50.00 


50.04 


Hydrogen 6.41 


6.4T 


Oxygen 25.64 


25.13 


Nitrogen ' 17.95 


18.36 


100.00 


100.00 


Its formula is C13H10O5N2. 





Albumen. 

Albumen is a component of nearly all the animal 
solids ; and when free from foreign matters is soluble in 
water. This solution coagulates at 160°, but the coagu- 
lum may be redissolved, by heating it with water in a 
digester at 400°. 

As precipitated from the aqueous solution of white of 
eggs, or of the serum of blood, it is pure and soluble in 
acetic acid, very weak alkalies, and in soluble alkaline 
salts. 

Albuminous solutions are precipitated by sulphuric 
acid J hydrochloric acid produces a coagulum soluble in 
water, and in strong hydrochloric acid by heat. Nitric 
acid throws down a flocculent precipitate, soluble in alka- 
lies even from very dilute solutions. Acetic acid gives 
no precipitate even by heat, unless both acid and solu- 



PROPER TREATMENT OF HIDES AND SKIN. 173 

tion are concentrated. In that case, a gelatinous com- 
pound, soluble in both acid and in water, is formed ; 
albumen is soluble in alkalies ; water of lime, baryta and 
strontia have no reaction upon the aqueous solution of 
albumen, but with the alkaline earths themselves, it forms 
insoluble compounds. Earthy and metallic salts throw 
down double compounds, one with acid and another 
with metallic oxide, the latter of which is wholly insolu- 
ble, while the former is not entirely so. 

Tannin precipitates albuminous solutions, but the 
resulting compound is not softened by heat like the 
tanno-gelatine. 

Pure albumen is thus formed : — 

Carbon . . . . . . . . 54.84 

Hydrogen. . . . . . . . Y.09 

Nitrogen 15.83 

Oxygen 31.23 

Phosphorus / . 0.33 

Sulphur 0.68 



CHAPTER XIX. 

THE ^PROPER TREATMENT OF HIDES AND SKINS— KINDS 
OF SKINS SUITABLE FOR TANNING— SALTING OF THE 
HIDES. 

Proper Treatment of Hides and Skins. 

Mr. H. F. Lange, Cordovan leather tanner, in the late 
session of the Oschatz Trade Association, expressed his 
regrets that in the process of fabrication, that is to say, 
in the preparation of the hide for trade purposes, raw 
hides and skins labored under great disadvantages owing 
to the farmers' and butchers' handling, inasmuch as this 
was not carefully enough done with a view to the future 



174 CHEMISTRY OF TANNING. 

operations to be undergone by the raw material. This 
subject of complaint was also concurred in by the bark 
and white tanners present at the meeting, who gave ex- 
pression to the united wish that through the making 
known of the manipulations which experience has proved 
to be the most simple, and, at the same time, the most effi- 
cacious, hides or skins may be delivered in a condition 
perfectly suitable to the process of manufacture, and the 
evils more closely particularized below might gradually 
be done away with as much as possible. , 

It happens only too often that the hides and skins of 
slaughtered animals, or of those that have died from 
natural causes, are not at once taken off, but left for 
days together on the carcass. This is in the highest 
degree detrimental to the hides, as they acquire thin and 
defective spots, through the process of decomposition 
going on in the carcass, or the worms which are forming 
in the interio^ of the animal work destructively upon 
the hides. Great damage is also caused, although of not 
so great a nature, if, in flaying, the work is not done with 
all due care. The bits of flesh and fat, which are only 
too often allowed to remain adhering to hides and skins, 
become at once decayed and communicate decay to the 
skin; which is injured or eaten away in spots, becoming, 
consequently and subsequently, very thin or even worn 
into holes. Such damage is noticeable in a more especial 
manner after manufacture, when the leather is found 
bad in appearance, or inoculated with dark spots, as is 
the case with colored leather. 

And leaving these defects out of the question, the 
suppleness and durability of the leather itself will be in- 
juriously affected if the skins, are not suitably and care- 
fully treated in drying and hanging up, by the premature 
shrinking and imperfect drying of the material. 



PROPER TREATMENT OF HIDES AND SKIN. 175 

As an evidence that the evils just mentioned, arising 
from improper treatment, are of more importance than is 
generally thought, we give the statement of Mr. Lange 
to the effect that the sheepskins received in the summer 
season often yield barely one-third of a material perfectly 
adapted to the fabrication of imitation morocco leather. 

In view of these evils, and in order to promote the 
interests of the leather trade, the following points are to 
be urgently recommended to the producers of the raw 
material in flaying hides and skins : — 

1st. Immediately after the death of the animal the 
hide or skin should be carefully taken off. 

2d. The fleshy or fatty portions still adhering to the 
skin should be detached down to the smallest pieces. 

3d. The hide should, without the least delay, be hung 
up in a very airy place, one not exposed to dampness, 
with the hair side inward, so that a draught of air may 
play upon the entire length of the inward side of the hide. 

4th. In order to prevent the hide from shrinking, the 
head and tail ends should be stretched out, and nailed 
to the pole. 

5th. The hoofs and legs should be spread with skewers 
on both sides. 

6th. The flaying of the hide should not be intrusted 
to inexperienced persons ; for, unless a certain dexterity 
is brought into this operation, the value of the skin will 
be considerably lessened. 

Only by observing these directions can skins and hides 
be properly dried, and delivered free from defects, suit- 
able for valuable use. 

The benefits that will accrue to the whole leather trade, 
by following such a course, cannot be rated too highly ; 
for not only will it secure a serviceable material to man- 
ufacturers, but also a large quantity of hides and skins 



176 CHEMISTRY OF TANNING. 

will be saved from destruction, and the market will be 
better and more fully supplied. A further consequence 
will also be that a better manufactured article will be 
produced, and lower prices be established. 

Kinds of Shins suitahle for Tanning. 

The principal object of attention in the preparation of 
leather is the hides or skins of the animals. Three classes 
are specified in commerce : the term hide is applied to 
the skin of the larger and full-grown beasts; hip to 
the skin of the younger animals of the same class ; and 
shin indicates the hides of the sheep, goat, kid, and the 
like. The term hip is qualified by the size of the skins. 
Generally speaking, the skins which are converted into 
leather are those of oxen, cows, and calves, of the sheep, 
the goat, and their young, of the horse, the pig, the dog, 
and a few others ; but by far the most extensively worked, 
as well as the more important, are ox, cow, and horse- 
hides, kips, calf and seal-skins. Considerable difference 
is observed in the thickness and quality of the skins of 
various animals, even of those of the same class, owing 
to circumstances connected with the food, age, variety 
of breed, the state of health, and even the period of the 
year when they are slaughtered. Thus, large oxen are 
well known to afibrd hides which are tanned into thicker 
and heavier leather than bulls or cows, especially if the 
latter be old and have had several calves. Bull-hides 
are coarser-grained, and thinner in t^e back than those 
of oxen and heifers, or young cows, but much denser in 
the neck and parts of the belly. It would also appear 
'►.that when cows have repeatedly calved, the skin becomes 
distended and thinner, and does not, therefore, afford as 
heavy a sole-leather as that of younger animals. Again, 
hides of animals, dying in a state of disease, are found 



PROPER TREATMENT OF HIDES AND SKINS. 1.77 

to be much ii^erior to those of healthy ones of the same 
class, although the apparent difference is not very marked 
before tanning. 

No very definite criteria are known to guide the pur- 
chaser in distinguishing the quality of hides and skins. If 
the hide be thin, flabby, soft, and will not bear handling, 
then such a one will not make good leather; but should 
it present the opposite quality, it may confidently be 
expected to be a good article. It has been remarked of 
sheep, that the finer wool variety have inferior skins ; 
also that the skin gains in thickness and quality con- 
siderably in the course of a few days after shearing. 

Ox-hides. — Under this head may be enumerated the 
skins o^oxen, cows, buffaloes, and calves. In Great Britain 
and Ireland, the market drawls generally upon the home 
produce, but the largest quantity used comes from South 
America, the East and West Indies, etc. The animals 
which roam along the Pampas and Llanos, or great 
plains, in herds of vast numbers, are, in addition to 
those owned by the extensive cattle owners or hateros, 
the stock whence the vast quantity of hides used is an- 
nually derived. They are imported in the dry state, 
and salted, and produce a very good sole-leather. Il 
should be remarked, however, that the hides from ani- 
mals inhabiting the tropical latitudes are not so well suited 
for tanning as those from the temperate and northern 
parts of the globe. The green or fresh hides of the home 
market always r^e higher than other sorts, owing, per- 
haps, to the fact that they do not require so much labor 
as the imported dry kinds; still, in consequence of the 
amount of water they contain they prove to be much.* 
dearer than the others ; for, allowing that for the pro- 
duction of 100 pounds of leather. 75 pounds of dry hide 
are requisite, the equivalent of this of salted hides would 
12 



178 CHEMISTRY OF TANNING. 

average 150 pounds, and 185 of green or, market hides. 
Heavy hides are converted into sole, belt, and harness 
leather, also for carriage coverings, and the smaller and 
lighter kinds are made into leather much used for shirt- 
ings, and for enamelling. That which is used for ladies* 
shoes and for bridle leather, undergoes a bleaching 
process termed fair finished. Hides from the west coast 
of Africa make good upper leather, but are much em- 
ployed in their raw state for trunk covering. 

Calves' skins and hips of home produce are of very 
superior quality, and produce a leather, when made with 
good oak bark, very extensively worked into uppers of 
shoes and boot fronts. In France, where the calf-skin 
leather has been reputed for its excellence, they are 
taken off the animal when five or six months old. Kips 
are imported from the East Indies, Buenos Ayres, and 
Montevideo ; those from the former places are dried and 
salted or merely exsiccated ; and from the latter places 
they come simply salted. The lesser and inferior kinds 
of kids and calf-skins are tanned for bookbinders' use, 
for gloves, and the manufacture of ladies' boots and shoes. 

Buffaloes' hides are tanned like ox-hides, but they make 
an inferior quality of sole-leather. When tanned in a 
particular way with oil, they constitute what is termed 
hvff-helt leather, which is superior to the similar article 
made of cow-hides. 

Horse-hides. — The skins of these animals are much 
inferior to those of oxen in thickness, texture, and 
strength, and, consequently, they are never prepared with 
the view of making sole-leather, though the better quality 
is used when tanned for uppers. The chief consumption 
is, however, as cordovan or enamelled leather, the hides 
being split by machinery to reduce them to the adapted 
thinness. Horse-hides are likewise made into tawed, 
white, or alum leather, and are in this state used as aprons 



PROPER TREATMENT OF HIDES AND SKINS. 179 

for certain classes of mechanics, and as thongs for the 
manufacture of common kinds of whips, and for sewing 
common harness. 

A considerable number of horse-hides is annually im- 
ported from South America. The imported hides are 
much superior to those which find their way to the home 
market, on account of the latter belonging generally to 
old and worn-out animals, while the former have been 
flayed from the captured wild horses of the pampas, 
lying between the chains of the Andes. Ass and mule's 
hides, tanned and so prepared, serve for the manufacture 
of scabbards ; the leather is called shagreen or sliagri. 

Sheep-shms. — The home supply is very extensive, 
and although they are capable of making only a spongy, 
weak leather, the uses to which they are devoted are 
various, and their manufacture gives employment to 
numerous hands. Tanned with bark they constitute 
bazils, and are used for making slippers and as bellows 
leather ; but when prepared with alum and salt, or with 
oil, white leather, much employed for aprons and by 
druggists, chamois leather result. A good many are 
split, the upper or grain side being tanned with sumach 
and dyed, then worked up as shiver, roan and morocco 
into pocket-books, hat-linings, and the under portion 
being made into white leather, and used very much 
by the chemist ; but it is much the more general practice 
to reserve lamb-skins for the latter purpose ; sheep-skins 
are sometimes tanned with the wool adhering to them 
and made into mats. In Asia Minor a considerable trade 
rises from the preparation of lamb-skins for ladies' glove- 
leather, for lining of morning-gowns, for slippers, and 
for winter gloves. On the hides from Asia Minor the 
wool is kept for the purpose of retaining the w^armth. 
Considerable difference may be observed in the quality of 



180 CHEMISTRY OF TANNING. 

lamb-skins; those from the animals killed shortly after 
being born are possessed of a very fine grain, and take a 
very uniform dye. The same qualities are in a great mea- 
sure retained by the skins till a month old, but from this 
period they begin to deteriorate. In the, Southern part 
of France and in Italy great numbers of lambs are killed 
averaging four weeks old, and the leather prepared and 
employed as a substitute for kid leather. 

Goat-skins. — In this country a number of native skins 
are used, but the market is supplied almost entirely by 
imported goods, more especially from Switzerland, Mog- 
adore, the Cape, and the East Indies. The Swiss 
skins are more esteemed because they possess a close, 
fine, and equal grain, which enables the dyer to give them 
a brilliant and permanent hue; the leather is also 
stronger, and weaves better than any other manufac- 
tured from goat-skins. Mogadore skins are made into 
a kind of black morocco leather, which still goes by the 
title of Spanish leather, or cordovan, in consequence of 
the first supplies of this article being obtained from 
Spain and Cordova, where the Moors originally brought 
the manufacture to great perfection. The sound skins 
which arrive from the Cape of Good Hope are much 
larger and superior in strength and thickness to any 
other variety. East India skins are small and light, 
and are generally converted into leather chiefly used for 
ladies' shoes and upholstery. Those from Mexico known 
as Tampwo skins bear a very high character. Compared 
with sheep-skins, those of goats are much superior in 
tjexture, strength, and durability. Goat-skins are occa- 
sionally prepared so as to imitate chamois leather, and 
applied to most purposes to which the latter is adapted, 
and likewise with the hair on and used for matting. 
Kid-skins, manufactured into leather, are most exten- 



PROPER TREATMENT OF HIDES AND SKINS. 181 

sively consumed by the glover, also for shoes, binding 
leather and the like. 

Deer-shins. — A considerable number of these skins are 
manufactured into chamois leather, and also into glove 
leather. 

Hog or Pig-shins. — Tanned pig-skin constitutes a very 
porous, light, but, nevertheless, very tough and valuable 
leather. It is largely used by harness-makers for 
saddle seats. The practice of skinning pigs is followed 
in Europe, where the hide is dressed with the hair on 
and used to cover portmanteaus, knapsacks, etc. 

Seal-shins. — Of these a great quantity is imported 
yearly into France, and manufactured into upper and 
varnished leather. They are obtained from the animals 
captured along the shores of North America for their oil. 
The skin of the seal is light, but of a close texture, and 
when properly tanned, yields a leather which has greater 
strength, in proportion to its weight, than any other 
variety. Seal-skin is usually made into black enamelled 
leather for ladies' shoes. 

Porpoise-shins.— l^YiQ skins of the white porpoise have 
been tanned in Canada, and the leather is said to be 
soft, strong, and possessed of a beautiful finish. 

Hippopotamus Hides. — About one hundred of these 
skins are annually imported from the South of Africa, 
and are tanned with oak. The hide, originally of great 
thickness, assumes the appearance of boards after being 
tanned. The only use which appears to be made of 
them are implements used for beetling in washing, and 
bleaching cotton and linen goods. 

Mode of Salting Hides. 

Delalande's method, which is that generally employed, 
consists in laying the hides open upon the ground, and 



182 CHEMISTRY OF TANNING. 

sprinkling the flesh side with salt, more liberally at the 
edges and on the spinal portions than on other parts. 
They are then folded, or doubled lengthways, down the 
centre. The remaining folds are made over each other, 
commencing with the shanks, then the peak of the belly 
upon the back, afterwards the head upon the tail part, 
and tail part upon the head, and, lastly, by doubling the 
whole with a final fold, and forming a square of one or 
two feet. This being done they are then piled three 
and three together, and left until the salt has dissolved, 
and penetrated their tissue, which generally requires 
three or four days. Thus prepared they are sent to 
market. 

Skins may be dried, even after having been salted, 
by stretching them upon poles with the flesh side upper- 
most, and exposing them to dry air in a shady place. 

Ten pounds of salt in summer, and somewhat less in 
winter are requisite for. each skin of ordinary size. 



PART II. 

TANNING 



SECTION lY. 

PRELIMINARY TREATMENT OF SKINS. 

Hides, destined to be tanned and transformed into 
leather, are submitted to several preliminary operations 
before being tanned. We enumerate them successively. 
They are as follows : — 

Washing and soaking. 

Swelling. 

Depilating. 

Worhing on the Beam. 

Rinsing. 

Tanning. 



CHAPTER XX. 

WASHING AND SOAKING. 

The first operation that the skins undergo is the 
washing and soaking. It is, therefore, convenient to 
have the tannery located near by a stream of water. 
The skins are taken in a green, dry, or salted state. The 
green hides are those from recently slaughtered animals. 
They are soaked in water for half a day, or longer if 



184 TANNING. 

necessary, so as to remove all the blood and adhering 
dirt. They are to be well rinsed when taken out from 
the soaking. If they are to be soaked for a long time, 
it is necessary to handle them from time to time. 

If the current of water is rapid, trouble will be saved 
by planting a kind of rake across the stream, and fast- 
ening the hides so that the friction of the water may 
loosen the dirt and carry it off. The skins must be care- 
fully suspended, so as not to have them damaged by 
rubbing on the stones at the bottom of the stream. 

When the hides are dry the soaking should be con- 
tinued longer, and that operation is facilitated by hand- 
ling them often, and stretching them each time, beating 
them under foot, and working them upon the wooden 
horse, as shown in Figure 28, with the fleshing knife 
Figure 29, and then leaving them to drain. The fleshing 
is repeated once or twice. 

Fig. 28. 



Fig. 29. 




The working and scraping are continued until all ani- 
mal matters which are prone to putrefaction are removed. 
The length of time cannot be prescribed. The hides are 
to remain in water until they have become supple, and 
it is for the intelligence of the workman to determine 
when this point is attained. If the soaking is too long, 
the skins have a tendency to putrefy. Dried and salted 



WASHING AND SOAKING. 185 

hides require a much longer soaking than those which 
have been only dried. 

The working and softening of the hides upon the 
horse or beam are considered indispensable operations 
by every experienced tanner. 

When the skins have all been soaked and washed, and 
are sufficiently supple, they are returned and left in the 
water for six hours. In running water they may remain 
eight hours. Keference is here made exclusively to large 
hides, for cow-skins may be left without danger for 24 
hours, and calf-skins 48 hours, being careful to observe 
the nature of the water and the temperature of the air. 
Too long soaking in the same water exposes the skins 
to the danger of putrefaction, and the rapidity of the 
decomposition is proportional to the amount of filthy 
matters contained in the water. 

Well-salted skins, but not dried, may be cleansed in 
48 hours, but they can be left to soak three or four days 
without danger. They must be withdrawn once a day, 
left to drain two hours, worked with the back of the flesh- 
ing knife and well rinsed in water. The object of those 
manipulations is to remove salt and dirt, and render 
them soft and supple. When taken out from the water 
for the last time give a vigorous and thorough rinsing. 

At St. Saens they commonly use dry hides from 
South America, which are placed directly in'vats filled 
with lime-water and left for six or ten days, care being 
taken to work them in the usual manner at frequent 
intervals during the soaking. These vats are 8 feet long 
and 5 feet wide. 

The skins are softened by the action of lime and ren- 
dered more easy to be handled. At this stage the de- 
fective parts may be detected, and sometimes they are 
so damaged as to be suitable only to manufacture glue. 



186 TANNING. 

At Liege, where they mostly use the dry hides from 
Brazil and Caraccas, there is no, allotted time for soaking. 
After four or five days they examine each vat, and with- 
draw such hides as have become soft and leave the rest. 
This process is repeated daily until all the hides have 
been withdrawn. 

As soon as the hides are taken from the vats, they are 
worked upon the horse and then returned to the water. 
On the following day they are thoroughly rinsed and 
placed in the drying room. The working is solely for 
the purpose of removing the wrinkles and stiffness of the 
dry skins. These manipulations are unnecessary for 
green hides. 

According to some tanners the quality of the leather 
is improved in proportion to the duration of the soaking 
of the hides; but it is undeniable that when it exceeds 
a certain time the skin acquires a tendency to decompo- 
sition and the quality of the leather is impaired. 

Soahing of Foreign Hides. 

Before we speak of this soaking we must say a word 
or two regarding the employment of sulphuret of arsenic. 
This substance is produced by passing a current of hydro- 
sulphuric acid through a solution of arsenic. The sul- 
phuret is precipitated in the form of a bright-yellow, 
flaky substance. 

By mixing the orpiment with a solution of lime in the 
proportion of 4 parts of the former to 96 parts of the 
latter a compact mass may be obtained which is easily 
used for depilating purposes. 

Small hides or kips after being well washed and 
cleaned are soaked by laying them in foul bloody water. 
This method, which is of universal use amongst white 
tanners, requires much attention, like every other pro- 



WASHING AND SOAKING. 187 

cess by means of which the hide is almost restored to its 
original condition. It imparts a perfect softness to the 
hide, leads rapidly to the result, and is not costly ; but 
it requires the greatest precautions. The method to 
which we give the preference is the one that we now 
propose to mention as offering certain guarantees, as we 
have lately had proven to us by actual experiment. This 
method is the softening of the hide by sweating, that is 
to say, heating it without fire and without steam. 

The sweating pit is a pit about 12 feet long by 7^ feet 
broad and 6 feet deep, flat on the top. In order to se- 
cure the desired result it should be constructed of good 
masonry, and, when practicable, built under ground. 
Moreover attention should be given to have the access 
of the air removed as much as possible from the entrance 
to the pit. , The door, which should be 5 feet high by 
20 feet broad, must be made of strong pine wood and 
furnished with three bars strongly fixed, so that it may 
be made air-tight when closed, and not warp from the 
effect of the dampness which fermentation produces. 
The sweating vat should contain poles planted in the 
ground at intervals of about II feet, according to the 
breadth of the vat, and rise to the height of 5|- feet. It 
is important to observe these instances as nearly as can 
be, for if the sweating vat is too large, the same effect 
will not be produced. For sole-leather it is more desirable 
to use two smaller sweating vats than one very large one. 

Small hides or kips should be thoroughly washed in 
very clean water, spread out after four days' soaking, well 
rinsed and drained, then laid together in i^acks in such 
a manner that the hair is outward, and the pairs of skins 
back to back. Hang them over the poles of the sweating 
vat, with the tail end upon one side, and the head on 
the other. Then close the door and stop it up well so 



188 TANNING. 

that the air may be excluded as much as possible, and 
leave matters thus until the odor of the sweating process 
becomes quite strong, which is an indication that the 
process of depilation is about to begin. 

The working of the sweating process is shown by a 
sharp lye which forms under the hair, and which drops 
off the instant fermentation sets in. After taking the 
skins out, the thick portions should be worked with an 
iron instrument, then lay the hides in water and let 
them soak for a day or two, after which the flesh side 
should be worked with the stretching iron, in order to 
bring out the grain again before consigning them to the 
lime pit. 

Strange as this treatment of the hair side may appear, 
we do particularly recommend it, for in order to restore 
a cow-hide to its primitive condition, it is not sufficient 
to attend to the flesh side alone ; we require to provide 
against the remaining of wrinkled places on the grain, 
as often happens, especially in Java and Calcutta hides. 
When we come to dress the leather, these cannot be 
removed by the grainer or stretching iron, because we 
have neglected to give sufficient care to the grain. 

We cannot too often repeat that light hides should not 
be placed in too strong lime ; this sort of hides should 
rather be operated upon by degrees and always wdth 
weak lime, and for this reason, it appears to us, that 
the surest method that can be followed in order to 
secure a successful result, is to use lime that has already 
been weakened by contact with fresh hides. For a dry 
hide, when acted upon by lime, may be compared to a 
flower, which is taken out of a warm forcing-house, 
and exposed to a cold temperature. It will be seen 
that its development will be arrested, it will shrink and 



WASHING AND SOAKING. 189 

draw together, and never will expand any further. The 
comparison may be incomplete, but yet it is apt. 

With regard to the large hides of wild animals, such 
as those imported from La Plata and elsewhere, whether 
dried fresh or dry salted, we urgently recommend that 
they should be subjected to the sweating process, for, we 
repeat it, the sweating system has not only the effect 
of facilitating the process of depilation, but of giving to 
dry wild hides that development of which they stand in 
need. 

The sweating process, as we understand it, regulates 
and hastens the expansion of the hide, opens the pores, 
and places the hide in a state similar to that in which 
it was at the time the animal was slaughtered. To pre- 
pare it for the leather dressing process, it will be found 
enough to work the hide lightly on the flesh side with 
the iron, when it is taken out of the sweating vat, so as 
to stretch out the wrinkles that may appear before the 
hide is placed in the lime pit, which, as has been said, 
should always first contain a weakened lime bath. 

It is now for us to say something as to heavy hides, 
and it is necessary to state, that we restrict ourselves to 
the consideration exclusively of foreign hides, i e., the 
hides of wild animals. 

We will begin with dry hides, those coming from 
Buenos Ayres, for instance, as being the best known. 
What is considered the most estimable property of Bue- 
nos Ayres hides ? That they are a species of hide which 
softens easily and in a regular manner. It is admitted 
that hides which are allowed to remain continuously in 
water, soften less readily than those which are alternately 
soaked and piled. And now let us consider how piling 
compares with sweating. Piling is nothing more or less 
than a slow inward sweating, and while it is slow you 



190 TANNING. 

run the risk of having the edges damaged, by giving the 
time necessary to eflfect a good result. So in order to save 
the back and extremities, you are obliged to dispense with 
a complete softening of the hide, and moreover lose time. 
This is always the result of irregular soaking. Now 
what, in fact, do we seek to attain in soaking the hide? 
Simply the raising up of the fibres, in order to save those 
parts of the hide which were wet, and became dried dur- 
ing its transportation ; and we believe the best mode of 
doing this consists in accelerating the operation, so as 
to obtain a thorough soaking by the sacrifice of from 
seven to eight days. 

Moreover, stagnant and hard water does not give the 
dry hide time to become completely softened again, at 
least it injures the grain, which becomes lost before the 
water has had time to penetrate the fibres of the hide. 

Under these circumstances sweating is alone of use, 
and if necessary, a softening during 24 hours in open 
water will be sufficient to secure a satisfactory result, as 
experiment has proven. 

Soak the hides in water for 24 hours, mark the flesh 
side well, and rinse the hair side thoroughly, so as to rid 
it of all foreign substances, so that no faulty spots may 
ensue ; let them drain in a heap during four to five hours, 
and bring them to the sweating process as above des- 
cribed. Sprinkle them with fresh water through a gar- 
dener's watering-pot, provided with a sieve-like spout, 
and after the hides have been again allowed to drain off, 
put them back in the sweating vat. 

Three sprinklings with the watering-pot will be found 
ample, in combination with the sweating process, to soften 
the driest and oldest hides to such a degree, that, even 
if they are Of the heaviest, they can at once be divested 
of the hair. Then separate them after rinsing them, lay 



INFLUENCE OF THE "WATER UPON THE LEATHER. 191 

them again in running water, clean and scrape them, and 
do not interrupt the gradual course which the hide has 
to undergo. 

What we have last mentioned should only be resorted . 
to when suitable water is wanting for proper soaking, 
for we recommend above all things that the hide be care- 
fully soaked in water, as this raises it well, but in all 
cases, whichever mode of soaking be followed, the hides 
should never, as a general rule, be allowed to stay in the 
water longer than four days, or from five to six days in 
severely cold weather. Of course the sprinkling with a 
watering-pot is then superfluous, and there will then 
only remain the piling up of the hides in the sweating 
vat, to be attended to. They should be left in it from 
four to six days, according to the season of the year. 

With regard to salted wild hides, a proper softening 
in water will do, and this water should be changed every 
now and then, so that the hide does not remain long in 
briny water, and care should be taken to rinse them tho- 
roughly before placing them in the fresh water; for the 
rest the same course is to be pursued as with dry hides. 



CHAPTER XXI. 

INFLUENCE OF THE WATER UPON THE QUALITY OP THE 

LEATHER. 

It is a mooted point, whether the nature of the water 
used for soaking has any influence upon the quality of 
the leather. No positive experiments have been made 
yet, but in this case we think that it is better to take 
the aflirmative side of the question. Calf-skin leather, 
which should be soft and supple, requires soft fresh water, 



192 TANNING. 

and it will be difficult to manufacture tliem with hard 
water. 

Modern chemists call water protoxide of hydrogen. 
When pure it is inodorous, colorless, transparent, elastic, 
a good conductor of heat and electricity. It boils at 212°, 
and freezes at 32°. The waters called soft dissolve soap, 
while those which do not possess this property are called 
hard. The former is nearly free from soluble matters, 
while the latter contains calcareous and other salts. The 
composition of chemically pure water is in weight — 

equiv. 

Oxygen 1 = 8 = 88.88 

Hydrogen . . . . 1 _ 1 = 11.12 



9 100.00 
The agreeable taste of pure water is due to the air it 
contains ; when expelled by ebullition it is insipid. 

Bain Water. 

The purest rain water is that which falls in the 
country where there are no noxious emanations. 

The soluble impurities of rain water are those which 
it has dissolved from the atmosphere, and consist of 
minute traces of chloride of sodium, carbonic acid, 
and carbonate of ammonia. After a thunder-storm, rain 
water contains small traces of nitric acid formed by the 
atmospheric electricity. 

Snow Water. 
This water is the same as rain water, only it is crys- 
tallized, and by this crystallization it loses the gases 
held in solution. "^ 

Spring Water. 
Water, in its transit through the soil, becomes charged 
with such constituents thereof as are soluble in it; and. 



INFLUENCE OF THE WATER UPON THE LEATHER. 193 

consequently, the purity of the water is proportional to 
the insolubility of the earth through which it has flowed. 
The purest spring waters contain air, carbonic acid, 
and minute quantities of hydrochlorate and carbonate 
of soda. 

River Water. 

There is not much difference between river and spring 
water. Sometimes, however, it is purer from having 
deposited its suspended matter, and also a part of that 
held in solution, which generally happens when it tra- 
verses a long and silicious bed. If it pass over or through 
limestone, or other strata containing soluble ingredients, 
it becomes less pure. 

Lake Water. 

Lake water contains more soluble principles of the 
soil upon which they rest than river water ; this condi- 
tion is promoted by their state of quiescence. 

Marsh Water. 

This kind is in a more permanent state of stagnation 
than lake water. This water, on account of the organic 
matters it contains, easily enters into a state of putre- 
faction. 

Well Water 

Contains more soluble constituents of the soil than 
lake water. Well water is generally hard, because 
among earthy salts it contains particularly sulphate, bi- 
carbonate, and chloride of lime, which render soa^J in- 
soluble in it. 

Well water, in the vicinity of the sea, has a brackish 
taste, and contains the same constituents as sea water. 
13 



194 TANNING. 

When well water is very hard the addition of a little 
carbonate of soda will decompose the lime salt and 
render it potable. 

By what has been said it is evident that rain water is 
the purest, but all drinkable waters are applicable for 
tanning purposes. To soften hard waters the French 
tanners add a solution of pigeon or chicken dung to the 
vat, and stir it thoroughly by means of a shovel. The 
hides are then put into it to soak. Some tanners, instead 
of washing in the river, soak them in troughs. Water 
containing iron renders the leather brittle and blackens 
the hide. 

In Paris, the water is purified by filtering it through 
spent tan. There is a series of three vats, charged 
similarly with spent tan ; and as the water which is 
poured into the first vat is drawn through a cork at the 
bottom it is transferred to the second, and afterwards to 
the third. As, thus rectified, it contains a little tannin 
derived from the spent tan, which renders it particu- 
larly adapted for the early part of the tanning operation. 

Some waters are preferable to others for tanning, but 
on what particular quality of the water this superiority 
depends has not yet been determined. The safest way 
is to prefer those which contain the less soluble matters, 
particularly earthy salts, for they certainly reduce the 
tanning power of the ooze by combining with some of 
its constituents. 

The suspended matters, consisting of mud, as well as 
the soluble organic matters, which impart to water a 
bad taste, may be removed by filtering the water through 
clean gravel and fresh charcoal. 

If the lime exists in the state of bi-carbonate, it can 
be separated by adding to the water some lime-water. 
Boiling produces the same result. 



SWELLING OR RAISING OF THE HIDES. 195 



CHAPTER XXII. 

SWELLING OE RAISING OF THE HIDES. 

The second process to which hides are to be subjected is 
termed raising, and is that by which the pores are dis- 
tended, the fibres swollen, and the hair loosened. These 
results are effected by means of alkaline or acid solutions, 
and by fermentation. Milk of lime is the alkaline liquor 
generally employed. Lime-water has been proposed as 
a substitute, but it is less permanent in its action, and 
requires frequent renewal in order to insure the perfect 
cleansing of the hides.- 

Lime Process. 

This process, which is the oldest, is the most defect- 
ive, but in a complete work on tanning it is necessary 
to speak of it. It is an ascertained fact that the object 
of the vat work is to effect the swelling of the hide, 
to open its pores, and dispose them to the depilatory 
operation and absorption of the tannin. The tanner 
must be perfectly aware that he could never make a good 
leather with a hide which has not been well prepared in 
the vats. 

The vats are prepared in two ways : they are of wooden 
work sunk in the ground or masonry. The vats des- 
tined to swell the hides to facilitate the depilation and 
raising are more or less large; they are square or round, 
about i^ feet square and of the same depth. The num- 
ber of hides determines ordinarily the quantity of lime 
necessary for each vat ; one peck is usually sufficient for a 
large hide, while under some circumstances it is necessary 



196 



TANNING. 



to increase the quantity. In several manufactures to 
economize lime they add ashes, pigeon or dog dung, but 
we advise tanners to reject such processes. 

To make a new vat throw in it quick-lime, cover it 

with water, and stir well with a stirrer, as repre- 

Fig- 30. sented below, till slacked and reduced into milk. 

This operation done, leave a few days and it 

is then ready to receive the hides. 

The vats are distinguished as dead, weak, 
and live vats. The dead vat is that which has 
been nearly exhausted of its strength; the 
weak is that which has only been used long 
enough to deprive it of a portion of its force, 
^^ and the live vat is that which has not yet been 

worked. 
It is easy to understand that the live vat becomes 
successively the weak and the dead vat. When a tanner 
uses more than three vats he establishes between the dead 
and live vats as many middling terms vats as convenient. 
The whole of the vat is called raising series. 



Fig. 31. 




The raising should be commenced in the dead vat, 
and continued in consecutive order through the series to 
the live vat. In some factories the series consist of as 
many as twelve vats; and in this case there should be 



SWELLING OR RAISING OF THE HIDES. 197 

a graduation in the strength of the liquors. The dura- 
tion of this operation varies in different localities. Some 
tanners leave the hides for three months, while others 
soak them for eighteen months. 

There is great variation in the composition of the vats. 
In Auvergne and Limousin they mix with the lime, ashes 
or lye of ashes, and in some other places the lime forms 
only i in the composition of the vats. The old manu- 
facturers gave the hide a soaking of ten, twelve, and 
even fifteen months; and then when they have become 
sufficiently softened, transferred them to a dead vat for 
eight days; at the end of which time they were with- 
drawn, hung up for eight days, and again placed in the 
same vat for eight more days, etc. 

These consecutive operations are thus continued for 
two months or until the hair can be readily detached. 

The graduation of the vat varies in different localities. 
In Angoumois it consists of twelve vats; the first two are 
dead, the four following weak, and the last six fresh or live. 

In Poitou it consists of six vats; the first two are 
dead vats and the last three live vats. 

In Britanny many tanners who believe that the hides 
are raised better with the hair on than in pelt, give six 
live vats and do not remove until the fourth and even 
the fifth vat. 

In Auvergne they give three raisings of a month each 
with a mixture of lime and alkaline lye. 

So many vats are useless ; generally speaking, three 
or four vats skilfully managed suffice for any kind of 
skins. Some have asserted that ten to twelve months 
are requisite for a thorough soaking; but the experience 
of good tanners proves that two months are sufficient. 

According to Curaudau only ten or twelve days are 
required for the transit of the hides through the three 



198 TANNING. 

lime vats. He thinks a longer time will be useless, and 
that the shorter the soaking the greater is the weight 
acquired by the hides in tanning. 

Malepeyre says it is now established — 1st. That it is 
sujBficient to leave the hides in the pits for twenty-four 
hours, and an equal length of time in stack. 2d. That 
this operation should not continue for more than six or 
eight weeks. 3d. That three or, at most, four good vats 
are sufficient. 4th. That after this interval the hides 
are easily cleansed, and, on the other hand, where the 
treatment is prolonged the hides become parched. 5th. 
That after three or four pits, the hides will have swollen 
to the fullest extent, and finally there is a great waste 
of time, lime, and materials in the old method of steep- 
ing from ten to fifteen months. 



CHAPTER XXIII. 

STACKING OF THE HIDES. 

Stacking is to pile the hides one upon the other on 
the side of the vat as they are drawn from it, and leave 
them remaining a shorter or longer time before returning 
them to the bath for another wetting. 

Piling enables the working of 60 hides in a vat of 
a capacity for thirty, by having one bath taking the place 
of the other in alternate operations. While one set of 
thirty is in retreat the other should be in the vats, and 
vice versa. 

The vats should be covered ; and as the skins in re- 
treat are susceptible of becoming hard by exposure to the 
sun and air, they should not be kept in that state longer 
than is necessary. At every handling the water and 
lime at the bottom should be thoroughly stirred, and a 



STACKING OF THE HIDES. 199 

workman at each end of the vat, by the aid of tongs, 
arranges the hides in it so that they may be smooth 
and firm. The suspended lime soon subsides upon the 

'^ Fig. 32. 




hides, and the supernatant liquor which should cover 
the hides to a depth of some inches will be clear and 
transparent. As the greater portion of the lime is in 
contact with the skin at the bottom of the vat, its action 
is more powerful on them than on those above ; and con- 
sequently in recharging the vat after stacking, the order 
should be reversed. 

Should the vat become too weak to produce the 
desired effect, it must be strengthened by the addition 
of the quantity of lime necessary to restore its force. 
The advantage is thus obtained of giving the hide the 
benefits of two vats in one. The lime should be added 
while the skins are out of the vat. 

To remove the hairs, the scraping knife alone is used. 
It is a dull-edged instrument which is not liable to 
damage the skin by cutting it, while it is all efficient in 
scraping off the hair. It is a bad practice to use the 
slate or rubber, which, being rough, 
may scratch and damage the hide Fig. 33. 
upon its grain side. -^^^^^^^^ ^^^^^^ 

The use of sand, ashes, etc., for re- 
moving the hair is very improper; it is also a bad prac- 



200 TANNING. 

tice to wait until the completion of the soaking before 
scraping off the hair, because the lime will in time act 
on the hair itself. 

When the hair is removed, rinse the skins and re- 
place them in the dead vat, and so on. It suffices to 
leave the hides for fifteen days in each of these vats, 
but care must be taken to stack and replace them every 
twenty-four hours. 

M. Tournal says : " The force of habit and perhaps 
the use of the Kermes oak causes many tanners to con- 
tinue the use of lime. But if, in rinsing, great care is 
not taken to remove every trace of lime, the minute 
traces remaining will, by abstracting carbonic acid from 
the air, become insoluble and render the skin dry, brittle, 
and perhaps useless. These faults are not entirely due 
to the carbonic acid of the air, but also to the formation 
of tannate of lime and of stearate and oleate of the 
same basis which are generated by the presence of fatty 
matters existing in the hides. 

" Tanners who use the Kermes pretend that its warm 
nature imparts stiffness to the leather, and that the only 
available mode of raising is by lime. They own that the 
sour tan juice and barley processes distend the pores of 
the hides much more than lime, and that the tanning 
principle of the Kermes having a tendency to combine 
rapidly with the hide imparts an unnatural stiffness to 
the leather." 

To the above statement we will add that the bark of 
Kermes oak is richer in tannin than the ordinary oak, 
and admirable leather may be prepared by tanning 
with it skins which have been raised by sour tan liquor. 



INCONYENIENCE OF THE LIME PROCESS. 201 



CHAPTER XXIV. 

INCONYENIENCE OF THE LIME PROCESS. 

The inconveniences of the lime process are the 
following : — 

1st. The contact of caustic lime alters more or less 
the texture of the hide, and permitting it to penetrate 
the pores, it remains in them in the state of caustic 
lime, carbonate, or lime soap. 

2d. The rinsings in water and the workings remove 
it only partially, which is an impediment to perfect tan- 
ning. 

3d. It hinders the ready penetration of the tan liquor, 
and the perfect combination of tannin with the skin, 
and so obstinately resists removal during all manipula- 
tions that a portion is always found in the best 
leather. 

The experiments of Dr. J. Davy* show that the action 
of lime upon animal textures is rather antiseptic than 
destructive. Its cori-oding influence is limited to the. 
cuticle, hair, nails, and all gelatinous tissues. These 
latter become soft and gelatinous owing to a combina- 
tion which they form with lime, for on analyzing the 
ash of the cuticle thus treated a large increase of its 
normal contents of that earth was obtained. 

The matters were steeped in milk of lime, kept 
caustic in close vessels, by the entire exclusion of air. 
After treatment they cease to be putrescent. 

These disadvantages have led to the substitution of 
other agents, which we will proceed to treat of in the 
following chapters. 

* Chemist, 1850. 



202 ■ TANNING. 



CHAPTER XXV. 

METHOD OF RAISING BY ACIDS. 

An acid liquor has been used by some tanners instead 
of milk of lime. The Kalmucks use sour milk for this 
purpose. Pfeiffer has proposed the acidulated water ob- 
tained by the distillation of lime and peat. Sometimes 
a little sulphuric acid is added. This acid in a dilute 
state, as also all vegetable acids, produces the same effect. 
Acids have the double advantage of loosening the hair 
and swelling the hide. 

Some tanners soften the skins by sprinkling one half 
with salt, and folding the other half over it ; then they 
are piled and covered with straw. The fermentation 
follows; they must be turned several times daily, until 
they have attained that state in which they can be easily 
depilated. The use of salt is not necessary. They are 
to be piled on a bed of straw and covered in like manner. 
Twenty-four hours after they are turned and examined 
twice daily so as not to exceed the proper point. In 
some places the hides are imbedded in horse manure, in 
others they are covered with tan. The same effect 
could be produced by suspending the hides, which have 
been left l3^ing in a heap for several days, in a close room 
kept above the ordinary temperature by a smouldering 
tan fire. 

All methods of fermentation are termed sweating pro- 
cesses. But whatever is the process followed, the skins are 
to be spread upon a wooden horse, and scraped with a dull 
edged knife, as soon as the hair begins to yield readily. 
In this manner the hair and outer skin are fleshed or 



DEPILATION BY STEAM. 203 

scraped off. The outer skin being of a different nature 
from that of the hide, and not uniting with tannin, must 
be removed in order to allow the free passage of. the tan 
liquor through the skin, and to facilitate the tanning 
process. 



CHAPTER XXVI. 

DEPILATION BY STEAM. 

In many places, instead of a milk of lime, they use 
another method, which consists in submitting the hides, 
in the heap, to a slight putrefactive fermentation in 
heated chambers. In summer it is difficult to control 
this fermentation, and sometimes it is necessary to salt 
the hides. After some days the epidermis becomes loose 
and detached, and may be readily scraped off from the 
hair. 

Mr. Robinson, of Delaware, uses steam as the heating 
medium, in an arched chamber eighteen feet long, ten 
feet high, and ten feet in breadth, and lined interiorly 
with cement. The steam is introduced beneath a false 
bottom of wood, perforated with numerous holes. The 
condensed steam escapes through an opening at the 
basis of the chamber. 

. The temperature of the lieap should be maintained 
between 70° and 80°, and care should be taken to keep 
it uniform, for the joint action of heat and moisture may 
dissolve the gelatine and cause the hides to be scarred 
with pits. The process is completed in twenty-four 
hours, and the hair is scraped off in the usual manner. 
Ox-hides weighing from eighty to one hundred pounds 
experience a loss of twenty-four to twenty-eight pounds. 



204 TANNING. 



CHAPTER XXVII. 

DEPILATION BY CAUSTIC SODA. 

M. F. BouDET, for a substitute to lime for raising and 
depilating hides, proposes caustic soda. For this purpose 
the liquid is prepared by decarbonating a very dilute 
solution of soda ash with a sufficient quantity of lime, 
allowing repose, and decanting the clear supernatant 
liquor of caustic lye. Hides immersed in this liquor swell 
out rapidly and considerably, and are ready to scrape in 
two or three days. Moreover the alkali forming soluble 
salts with the fatty portions, facilitates the cleansing, 
and produces a smoother grained side than is common. 
Hides thus prepared imbibe the tan liquor more rapidly 
than those which have been treated with lime. They 
undergo the entire process of tanning in one-third of the 
time, and suffer less loss than those prepared by the usual 
method. Forty-four pounds of salsoda dissolved in one 
hundred and thirty-two gallons of water, and mixed with 
thirty-three pounds of slaked lime, suffice for steeping 
two thousand two hundred pounds of fresh hides. 



CHAPTER XXVIII. 

DEPILATION BY SULPHURET OP CALCIUM AND SODA. 

BouDET, in trying the old method of depilating by 
means of a paste of orpiment and caustic lime, observed 
that the arsenic had no decided influence upon the hair, 
and that the depilatory action was due to sulphuret of 



DEPILATION BY SULPHURET OF CALCIUM AND SODA. 205 

calcium in the nascent state, formed by the reaction of 
lime upon the orpiment (sulphuret of arsenic). He re- 
placed the orpiment by sulphuret of calcium, which, 
when made into a paste with lime, acted so promptly 
that, after twenty-four or thirty-six hours' contact, the 
skins were completely depilated. The lime alone has 
no depilating effect, and the sulphuret of sodium only a 
partial action. 

This mode of preparing the hide is said to render 
it highly susceptible of being quickly tanned. Experi- 
ence has to decide its influence upon leather. Tanners 
are opposed to this method, which, it is said, surcharges 
the leather with an amount of water that escapes by 
evaporation during storing, to the great loss of the dealer, 
but we do not think that this objection is tenable. 
Messrs. Abram & Coste use the following process : — 
Macerate the hides for three days, put them in the 
vat, raise three times, and then for each skin put 

Potash 2^ drms. 

Lime . . . . . . . 5 oz. 

Orpiment i oz. 

This same quantity is sufficient for three little goat or 
sheep-skins. For twenty-five hides take 

Potash 1 lb. 

Lime 2 lbs. 

Orpiment 2 oz. 

The whole is dissolved in fifty gallons of water. 

This vat is much less commended than the preceding, 
and is liable to numerous objections, and the principal 
is the danger to health accompanying its manipulation. 

Boettger has proposed to depilate all kinds of hides 
with the hydrosulphate of lime, in paste, which is pre- 
pared as we shall see hereafter. To use it, the skin is 
put, with the hair up, on a table, when the hair is 



206 



TANNING. 



slightly impregnated with the paste, so as to penetrate 
as far as the roots. In the same way is treated a second 
hide, and it is placed on the other. These two hides are 
covered with a board loaded with stones. Two hours 
after the hair is transformed into a kind of soap, which 
is easily removed. 

Preparation of the Eydrosulphate of Lime. 

The hydrosulphuret of calcium, or hydrosulphate of 
lime, is prepared by saturating a very thick milk of lime 
with sulphuretted hydrogen gas. The necessary appara- 
tus is shown below : — 



Fig. 34. 





It represents a leaden generator, of cylindrical form, 
thirty-six inches high by twenty-four inches in diameter, 
supported by a wooden jacket. This vessel has a mov- 
able cover of cast iron, with a projecting ledge, through 
which pass the bolts c, c, for fastening it down. In this 
cover there are three openings, as shown in Fig. 35. The 
larger one, g, is the man-hole for the admission of the 



DEPILATION BY SULPHURET OF CALCIUM AND SODA. 207 

sulphuret of iron and for cleaning out. Of the two 
smaller, the centre one, d, receives the stationary funnel 

Fig. 35. 




tube, d, through which the dilute sulphuric acid is to be 
introduced. The side hole, h, contains a short tube, &, 
with a screw at its u^per end for coupling the flexible 
exit tube, m (made of vulcanized rubber), which is to 
convey the generated gas into the lime paste contained 
in the closely covered receiver, x. A pipe running down 
the side of the generator, interiorly, is for the coupling 
of the steam pipe when the admission of steam is neces- 
sary. 

The protosulphuret of iron rests upon the bottom of 
the generator. When the sulphuric acid and water 
(one vol. of the former to three or four of the latter) 
are poured in through the funnel tube, d, to the height 
indicated in the figure, chemical action immediately 
ensues. The water, which is composed of oxygen and 
hydrogen, is decomposed, and the former gas goes at 
once to the iron, which is deserted simultaneously by 
its sulphur, and thus becoming an oxybase indulges its 
affinity for the sulphuric acid and unites with it to 
form sulphate of iron. The hydrogen unites with the 
sulphur to form sulphuretted hydrogen, which escapes 
through the tube, m, leading into the milk lime with 
which it combines as hydrosulphuret of calcium. The 



208 TANNING. 

current of gas is continued until the lime is saturated. 
When the current of gas slackens, hasten it by the 
addition of a little acid and water. The occasional 
admission of steam facilitates the reaction. When the 
paste is saturated, stop the connection of the tubes m and 
h. and the generator is emptied by the main hole, g, so as 
to be ready for another operation. 

The receiving vat should be of wood, strongly bound 
with iron hoops, and fitted with a cover and appliances 
for keepmg it close enough to confine the gas, but not so 
tight as to cause an explosion. 

The paste should be made in quantities as required, 
for it must be used immediately, as the action of the air 
soon converts it into sulphate of lime. 



CHAPTER XXIX. 

COOL SWEATING PEOCESS. 

This process, much used in New York, New Hamp- 
shire and the northern part of Pennsylvania, has all the 
advantages of the older processes. It gives a gain in the 
leather of 70 to 80 per cent., while the warm sweating 
process yields much less, and the liming only 30 to 40 
per cent. 

The process is described as follows :* "A vault or pit 
is prepared for the reception of the hides ; it should be 
12 feet long, 12 feet deep, and 10 feet wide. The wall 
may be built of stone or of a planked frame. There 
should be one alley for entrance six feet long, having 
a door at each end, the outer one made double, and filled 

* Journal Frank. Inst. 1843 



COOL SWEATING PROCESS. 209 

in with spent tan, to prevent the communication of 
warm air from without. A ventiduct, made of planks ten 
or twelve inches square should extend from the centre 
of the bottom of the vaults three or four rods therefrom, 
and placed not less than four feet below the surface of 
the groufld. This serves both as a drain for discharging 
the water of the vault and to admit damp cool air, to 
supply the place of that which has become rarefied, and 
thus keep up a current through the ventilator at the top. 
The ridge of the roof may be level with the ground ; 
and on the ridge, extending its whole length, set up two 
planks edgewise, two inches apart. The space between 
these is to be left open, but the remainder of the roof 
must be covered with earth, to the depth of at least a 
yard. The earth covering upon the vault and drain is 
to preserve a low temperature for the hides so that they 
may unhair without tainting. 

" Spring water should be conducted either in pipes 
or logs, around the angles formed by the ceiling with the 
walls of the vault, from which water should be allowed 
to flow in small quantities, either forming a spray, or 
falling so as to raise a mist or vapor, and saturate the 
atmosphere of the vault. The temperature of spring 
water is generally about 50°. Water evaporating at all 
temperatures, it is plain that if a constant supply be 
afforded, this evaporation, by requiring a large portion 
of heat, would keep the temperature of the vault nearly 
uniform. To suspend the hides in the pit, place three 
bars lengthwise, at equal distances, near the ceiling 
with iron hooks, two or three inches apart, inserted 
therein. Soak the hides as usual for breaking, then 
hang them singly upon the hooks by the butt, so that 
they may be spread fully open. In the course of a few 
days, when the hair begins to loosen upon the upper 
14 



210 TANNING. 

parts, take them down, raise the middle bar, and hang 
them by the other end until they easily unhair. The 
hides should not be broken until they are taken from 
the vault and ready to unhair. In a good vault where 
the thermometer ranges from 40 to 56°, which it should 
never exceed, and where there is a free circulation of 
damp air, hides require from 6 to 12 days for unhairing. 
When the temperature falls below 44° the ventilator 
should be partially closed, and when it rises above 56° 
cold damp air must be forced in, or an increased quan- 
tity of cold spring water may be thrown from a hose." 

Hides thus treated are free from all extraneous mat- 
ters, and contain all their gelatine, albumen and fibrin, 
in an unimpaired state. " The action," says the author, 
"is confined to the surface or grain of the skin, expand- 
ing the outer portion, softening the roots of the hair, and 
thus rendering its removal easy. The effect is due to 
the softening action of the vapour, and it is a simple case 
of absorption and swelling of the tissues of the skin and 
roots of the hair." 

This process has been proved by experience to obviate 
all the evils arising from hot sweating or from unhairing 
the hides by the lime process. 



CHAPTER XXX. 

EAISING BY BAELEY DRESSING. 

The swelling and depilation of hides by this process are 
more effective and rapid than when lime is used. Hides 
treated by this process require less working in the water. 

This process requires a series of vats varying in 



RAISING BY BARLEY DRESSING. 211 

strength. The hides are soaked at first in the vat con- 
taining the weakest liquor, then pressed and washed. 

Mr. Bouillerat, of Paris, operates as follows : The hides, 
after being soaked and fleshed, are put through the 
dressings, that is, are subjected to the action of barley 
water. They remain three days in the first or dead dress- 
ing, as much longer in the second, when they are freed 
from the hair, and placed in a third vat in which they 
dilate, swell out, and acquire consistence. They are 
taken out only once daily, from the dead dressing and 
twice from the others. At each time they are laid in 
heaps and there left during an interval of three hours. 
After these three dressings, the hides are submitted to a 
fourth, which is termed the new dressing, made with- 
145 lbs. of well-ground barley meal. From this quan- 
tity 10 lbs. are taken out and made into a leaven by 
being kneaded with warm water, and left to ferment 
from 12 to 14 hours, in which time it sours and becomes 
sufficiently ripe for the operation. In summer this 
leaven is thinned out with tepid water in sufficient 
quantity to form the dressing; in winter boiling and in 
spring hot water is used. 

From the new dressing, the hides are passed into an- 
other similar one and allowed to remain four days in each. 
Eight or nine hides are generally worked at a time. 

The series is composed of four or five vats. The first 
dressing is intended to wash the hides, the second for 
depilation, the third to swell them and impart body, and 
the two others, which are new, complete the action of 
the third. These preparations are termed white dressings, 
and require five weeks in summer and six in winter. 

After having gone through the white dressings, the 
hides are carefully washed and placed in the red prepa- 
ration, composed of 225 lbs. of tan well mixed with 21 



212 TANNING. 

hogsheads of water, and are left in the mixture for 15 
days in summer time, and one month in winter. During 
the first five days it is necessary to take the hides out, 
once daily ; to be sure that the supply of bark is sufficient 
when the skin comes from the preparation, they are to 
be washed and placed in the vats. Eight or nine skins 
may be handled at one working. 

At Abbeville (France) tanners have adopted the follow- 
ing method. For 16 hides, they put 48 lbs. of barley 
meal into an open-mouthed tub, and mix with it some 
sour paste made of flour thinned out with hot water. 
They add to this mixture ^ a lb. of yeast; fermentation 
soon follows, and in 15 to 16 hours the leaven is formed. 
• This leaven, being mixed with 150 lbs. of meal in a 
tub of water, forms the new dressing or preparation. 

The same gradation as with lime is observed as to 
these dressings. Before the hides are worked, they 
should be cut into halves, and always placed with the 
flesh side upwards. 

The time for the hides remaining in the dressing is as 
follows : two or three days in the old dressing, five or six 
in the weak, and twelve or fifteen in the third and fourth, 
which are the strong or new dressings. Sometimes the 
hides are sufficiently raised at the fourth dressing, and 
then they are taken out, while the unfinished ones are 
put into a fifth dressing and left until they have ac- 
quired sufficient swelling. 

During summer the hides are drawn out twice, and in 
winter once, and left to drain for an hour, each time, 
upon a trough conveniently situated near the vat. This 
operation requires about six weeks in summer and much 
longer in winter, for cold retards the action. 

In Sedan they use nine or ten small vats, each of about 
six hogsheads capacity. There is a regular graduation in 



, . RAISING BY BARLEY DRESSING. 213 

the strength ; for example, after the first operation the 
second becomes the first, the third second, etc. Five 
hides are placed in the first vat, where they remain 
from 24 to 48 hours ; they are transferred to the second, 
which is a little more sour, and so on successively through 
all the vats. It often happens that the hides attain 
the necessary degree of dressing at the fourth, third, etc. ; 
then it is useless to treat them further. These sour 
liquors, after having served for ten operations, still re- 
main acid, and can be used again according to their degree 
of strength. 

After the skins have been treated, they are washed in 
clear water for the removal of the dirt, and when they 
come to the last dressing they are rinsed and scraped 
over with the fleshing knife; at last they are again put 
in water and brushed over on the hair side. 

Some, after this manipulation, lay the hides in the 
vats, but the greater number subject them at first to a red 
dressing. This dressing is given by spreading the hides 
in a vat, one above the other, and placing between each 
pair two or three handfuls of ground bark. They add 
water until the hides are submerged. This process re- 
quires two days, and the hides require only one with- 
drawal to allow them to drain. 

Fig. 36. 




In giving the finishing wetting, care must be observed 
to supply bark where it is wanted. 



214 TANNING. 

This method of cleaning and unhairing presents as 
many objections as the lime process, and besides has 
other disadvantages. The efficiency of the bath is 
destroyed when exposed to a low temperature, and it is 
not restored when the bath thaws. The leather is ex- 
posed to be injured by the putrid fermentation of the 
materials. 

In England, for coarse hides, they have used for a 
long time the barley dressing, and they complete the 
operation in six days. The hides pass through four 
or five dressings, and from the weak progressively to the 
strong. The hides remain 24 hours in the last vat, 
which is new, and has been soured for 15 days. It is 
made by mixing 60 lbs. of barley meal in hot water. As 
a long time is allowed for the development of acid and 
consequently the dressing is more active than ordinary 
ones, it becomes necessary to w^atch carefully when the 
required point is reached, otherwise the hides will be 
injured. 

Barrois operates differently. He works five se^fies of 
four tubs each, at a time. These vats are 3^ feet high 
and 5 feet in diameter, and of a capacity for 8 hides; 
each series comprising 32 hides. It is necessary to take 
out all the hides twice daily during the dressing. Every 
•four days a new preparation is made up in one of the 
vats, which is deposited in that, the dressing of which was 
the weakest after running it off and washing out the 
vat. The third vat then becomes the last, and tliat 
which was the first and strongest becomes the second. 

The hides remain eight days in the fourth or weakest 
vat, four days in the third, which then becomes the weak- 
est; then the same length of time successively in the 
second and the first, after remaining six days in which 
they are stripped and deposited in a fresh series. In 



RAISING BY BARLEY DRESSING. 215 

this they remain four days in a dressing which has only 
been used once, four days more in another similar one, 
and four days each in two fresh vats. 

Each fresh preparation for eight hides is composed of 
145 lbs. of ground barley, and the leaven is made with 
30 lbs. of the above barley mixed with yeast and hot 
water. 

This interval of thirty two days is sufficient for the 
requisite preparation of the hides, either in summer or 
winter; but in the latter season, hot water is generally 
used in the proportion of five to six buckets to each 
preparation in order to hasten the fermentation. 

A hide dressed by this process weighing 100 lbs. takes 
about 200 lbs. of bark as follows : 25 lbs. in the red dress- 
ing, 30 in the first powder, 25 in the second, and 20 in 
the third. The preparation is maintained fresh by the 
addition of a few pints of vinegar. 

When the hides have been sufficiently raised in the 
white dressing, they are put in the red, which is composed 
of clear water and two or three handfuls of bark placed 
between the hides. The hides remain thus three or four 
days, when they are again treated by the same quantity 
of bark as at first, and left three days longer ; after that 
time they are ready to be laid in the vats in the same 
manner as in the lime process. 

This process, a little modified, is one of the best that 
can be followed. A fresh vat can be used every two 
days, and thus there will- be a gain of half of the time. 
Instead of clear water, it is better to use the liquor of 
the tan pits, and to place between each hide a layer of 
coarsely groiind bark for the red dressing. 

Two hundred pounds of bark are not sufficient for 100 
hides averaging 200 pounds each. In some places they 



216 



TANNING. 



use 300 lbs., but the quantity depends mucli upon the 
quality of the bark and the fineness of the powder. 

The following is a very good method : For a dressing 
for eight hides averaging 50 lbs. each, from 100 to 140 
lbs. of barley meal must be employed. Some tanners use 
all the meal at once, but others again make a leaven 
with 24 lbs. of the meal, which they do not mix with 
the rest until twelve hours have elapsed. Many tanners 
keep up the acidity of the dressing by throwing into 
each one three or four bottles of vinegar, at different 
times. 

Other tanners put the whole of the meal in the tub 
and drench it with enough tepid water to form a fermen- 
table paste, and leave it twenty-four hours. The dress- 
ing is made by adding to the fermented flour warm water 
in winter, and water at the ordinary temperature in 
summer. The quantity of water varies according to the 
number of hides. These are divided into two sides before 
subjecting them to the dressings, in which they remain 
three weeks in summer and four in winter. The hides 
are taken out daily, and placed on planks across the vats 
as shown in the figure, and there left for two or three 

Fig. SI. 




hours. The vats are 4i feet in height and as great in 
diameter. In some places, tanners use nine or ten 



vats, but three are sufficient; 



the first for the dead^ the 



RAISING BY BARLEY DRESSING. 217 

second for the feeble^ and the third for the new prepara- 
tion. The depilation is performed as soon as the hair 
can be pulled off without resistance. 

Scrape the hides with the usual precaution, with the 
round knife, and throw them into the w^ater, where they 
remain about two hours. Kinse, draw out, and place 
them in the second preparation. Experience alone de- 
termines the length of time necessary for the weak bath. 
While they are attaining the requisite body, they must 
be taken out daily, and replaced in the vats. 

If the hides have not been fleshed before the dressings, 
it is necessary to subject them to this operation, after 
drawing them from the weak vat ; but it is better to do 
it previously. After the fleshing, soak them for two 
hours in water, rinse carefully, and place them in the 
new dressing, which is prepared with barley meal, in the 
proportion of twelve pounds for each hide. A leaven is 
made with one-fourth of this quantity of meal, and when 
it begins to ferment, the residue is added, and the whole 
thoroughly difiused in an amount of water proportional 
to the number of hides to be worked. 

The time in the third dressing varies according to the 
nature of the hide, the season, &c. 

The hides during this, as in other dressings, should be 
daily removed from, and replaced in the vats. 

The hides are then put into the red dressing, made of 
liquors from the tan vats, to which must be added about 
6i lbs. of coarse bark for every hide. 

You must be careful, in this operation, to avoid delay, 
and not give the bark time to settle to the bottom of 
the vat, for the skins will be unequally tanned. 

It is better to commence work with the red dressing 
very early in the morning, so that the operation may be 
completed before night, and the leaving of the skins too 



218 TANNING. 

long without stirring should be avoided. This way the 
hides may be taken out and replaced twice daily, once 
in the forenoon and once in the afternoon. The first 
time they are allowed to drain ten minutes, and then 
replaced. The second time they are drained for fifteen 
minutes, and in the interval the same amount of bark is 
added, and the vat thoroughly stirred. The next two 
days the hides are taken out and put back three times 
daily, and left to drip half an hour each time. Twenty- 
five pounds of fresh bark are added in the morning, and 
upon every removal of the hides the dressing is carefully 
stirred. No bark is added on the fourth day, and the 
hides are taken out only twice, and are allowed to drain 
three-fourths of an hour each time. 

The last step, upon the fifth day, requires a new mani- 
pulation. After the hides have been taken out in the 
morning, and drained three-fourths of an hour, two 
workmen stir up the contents of the vat, while two 
others put back the hides, flesh side down, care being 
taken to spread some handfuls of bark upon each. When 
the vat is full, the last skin is put in with the hair side 
down, and some bark is sprinkled over it. After ten 
days take the hides out, rinse them in water used for 
dressing, and lay them in the vats. 

The red dressing is a very important step in the pro- 
cess of tanning. It gives firmness to the hide, by an 
incipient tanning, which serves as preliminary to that 
which is to follow. A skin which has not received a red 
dressing is tanned so rapidly that it shrinks, becomes 
hard, wrinkled, and insusceptible of perfect combination 
with the tannin. The feeding of the vat, according to 
Dessables, can never be too strong, for the hide neither 
hardens nor shrinks in the powder. However, we be- 
lieve that a strong feeding of a vat is injurious. Experi- 



WALLACHIA LEATHER. 219 

ence has proved that with a hide directly in contact with 
a concentrated liquor of bark, the tanning is very active, 
but the combination of the tannin with the gelatine is so 
rapid upon the exterior surfaces that the interior is un- 
acted upon, as is the case in hasty tanning. 

There are some tanners who contend that barley- 
dressed hides require about twenty per cent, more bark 
than those which have been limed. In many places 
they take for a barley-dressed hide averaging 1 00 lbs. in 
weight 225 lbs. of bark, as follows: 84 for the first, 75 
for the second, and 66 for the third. The same results 
can be obtained with rye flour. 

We do not recommend these processes to manufac- 
turers; their use is now abandoned in consequence of 
the uncertainty of their action. We shall speak now of 
Wallachia leather, which is similar to this process. 



CHAPTER XXXI. 

WALLACHIA LEATHER. 

This kind of leather is manufactured in Wallachia, 
and is made by barley-dressing, in a single vat. The 
hides are softened in water, and trampled under foot, 
then worked on the flesh side with the scraping knife to 
render them supple; at last they are rinsed in water and 
hung up to drain. They examine then if the hair can 
be easily detached, for, in warm climates, in summer, 
this is effected without any other preparation. If fresh 
skins are used, they are left to ferment so as to remove 
the hair, and, after removing the tail, horns, and ears, 
the skins are salted without being soaked. 



220 TANNING. 

The salting consists in sprinkling over each large hide 
from four to six pounds of salt, alum, and saltpetre, 
doubling it on the centre, so that one half is folded over 
the other, stacking it, and covering the pile with straw. 
The hides soon become heated, and it is then necessary 
to turn them once or twice daily, and change the 
folds, and the sides, so as to insure a uniform fermenta- 
tion. When the hair can be detached readily, the depi- 
lation is immediately commenced, ■ for any delays are 
injurious to the grain of the leather. If they cannot he 
depilated immediately, soak them in water for one or 
two days, but no longer, for fear of their undergoing an 
incipient fermentation. 

Salt is not necessary, as we have said above ; as a 
general rule the hair should give with a noise, when it 
is plucked out with the fingers, and the more difficult the 
depilation the better the skin, as it is a proof that it has 
suffered no alteration. The parts denuded during or 
previous to the operation should be moistened with a 
solution of salt, so that they may not be overheated 
before the other portions are ready for the depilation. 

The depilation can also be effected with the help of 
stable manure. The three methods by fermentation are 
the most objectionable, as the skins nearly always suffer 
more or less from incipient putrefaction. In the follow- 
ing method it is better to employ the exhausted vats. 
As soon as the depilation is finished, the raising is 
effected in the following manner : — 

For seven hides, each averaging eighty pounds, take 
twenty pounds of wheat flour that you make into a 
leaven, diffuse in water to a pasty consistence, and, to 
accelerate the fermentation, add a gill and a half of vin- 
egar. This leaven requires twenty-four hours to be 



WALLACHIA LEATHER. 221 

made, after which it must be kept covered in a warm 
place for three or four days. 

The tub for six or seven hides should be five and a 
quarter feet in diameter, and three and a quarter feet in 
height, and well cleansed. Fill it with water and with- 
draw from it six or seven bucketsful, boil^ and use a 
part for making a uniform paste out of ground barley, 
which afterwards thin out with cold water till of a 
syrupy consistence. This paste is boiled till it froths, 
constantly stirring with a wooden paddle, and when it 
has bubbled or foamed three times, it is to be poured 
into the tub destined for the dressing, and cooled by 
stirring with the paddle kept moving constantly in the 
same direction. The temperature should be such that 
the hand can be kept in it. Then stir in six pounds of 
salt, cover the tub, and leave it two weeks to sour. How- 
ever, the mixture is stirred twice daily, and, in order to 
confine the heat, the cover should not be kept off longer 
than is necessary. 

Take the skins from the rinse-water, strung in threes 
upon a rope thrown into the tub, and leave for four or 
five days. Each day withdraw them twice, rinse, leave 
to drain a minute, and put back in the tub. When the 
skins are well broken, and the hair side has become 
sufficiently soft to retain the impression of the finger- 
nail, they are taken out and fleshed. If some portions 

Fig. 38. 



of the hair should still adhere, spread the hides upon the 
beam, and scrape them with the knife represented in fig. 
38. When shaved, rinse in clean water, suspend and 



222 TANNING. 

leave to drain twenty-four hours. In the mean time 
make and ferment in the same way a second leaven with 
sixteen pounds of meal. 

The sour liquor is then transferred from the vat of 
the first dressing, and the clear supernatant portion 
poured into the second tub wherein is to be given the 
complement, which is nothing more than a repetition of 
the preceding operation. Six or seven bucketsful of the 
clear sour water of the tub are taken from each vat, are 
boiled, and a portion stirred up with about fifty pounds 
of ground barley, or about eight pounds for each hide. 
Add gradually the residue of the hot water, boil gently, 
and distribute in the new dressings, stir, take out a 
bucket or two, and heat it nearly to ebullition. The 
second leaven, made with eight pounds of meal, is dis- 
tributed in the tubs ; add to each four or six pounds of 
salt and and stir well. Take out several bucketsful and 
hold them in reserve, so as to have them ready for sup- 
plying any deficiency in the quantity of the liquid, which 
should not be greater than eight inches in height. If 
this method is too tedious, it may be simplified by mak- 
ing one step of the two, and using at once thirty pounds 
of leaven, one hundred and twenty of barley, and ten of 
salt, for each dressing of six hides. 

By the ordinary process, tanners use at one time in 
their first new dressing, just twice the quantity of barley 
that would be employed here, and when their first new 
dressing is not sufficient, they make a second, which 
renders the process more tedious and costly than that of 
Wallachia. It is also necessary to say that, on the addi- 
tion of salt, the dressing must always be well stirred, 
and two or three bucketsful of the liquor drawn out 
from each, and kept warm, to be poured into the vat in 
order to maintain the temperature. Several other 



WALLACHIA LEATHER. 223 

bucketsful are poured into a reserved tub, so that no 
more liquor may remain in each dressing than is sujffi- 
cient to cover the skins subjected to its action. Some 
tanners think it better to make the whole of the composi- 
tion at once, for it may so happen that the complement 
made with the new quantity of barley may retard the 
progress of fermentation, and that the liquor must then 
be heated to a temperature which would be injurious to 
the skins. 

The single composition is made in different ways : 1. 
From barley or rye meal without leaven, prepared over 
night with boiling water. 2. From equal parts of bar- 
ley, meal and leaven, thinned out with water and heated 
nearly to ebullition just previous to putting in the' skins. 

3. From wheat bran in the proportion of a half bushel 
per hide, thinned out with hot water, and after a day's 
fermentation mixed with one pound of salt for each hide. 

4. From leaven of barley or rye as substitute for that 
from wheat in the proportion of 6 to 8 lbs. of flour per 
hide. When the leaven rises, thin it out with water at 
86°, and add the salt just before the skins are put in. 

METHOD OF WORKING THE DRESSINGS. 

When the fermentation is well established the dress- 
ings are ready to receive the skins; then take them from 
the hangers, and pass them in and out of the liquor 
several times to gradually equalize the temperature. 
Leave them a few minutes, on the cover of the tub, to 
drain. Stir the liquor and put back the skins, cover 
the vats, and maintain the heat of the dressings with 
the liquor kept warm and in reserve. Fifteen minutes 
after take out the hides, let them drain fifteen minutes, 
and put them back. Half an hour after remove them, 
let them drain a quarter of an hour, return them to the 



224 TANNING. 

vat, and take them out again to drain twenty minutes. 
At last they are taken out after two hours, and the 
same round is repeated a seventh and eighth time after 
a similar interval. The liquor must be stirred every 
time, so as to cause the meal to rise from the bottom. 
Be careful to cover the vats immediately after putting in 
the hides. The heat of the vats should be maintained 
at from 105° to 120° F. by additions of reserved liquor 
kept warm. 

Two workmen place the hides in the vats; they take 
them by the opposite ends, spread them out upon the 
flesh sides, and then push them down with a pole. 

The action of the white dressing is ■ completed in 
thirty-six hours ; the acetic fermentation so expands the 
hides that they become as thick as leather into which 
they are about to be converted. Care must be taken 
not to leave them in the liquor after this point has 
been attained, for it injures the leather. The same 
result occurs if the liquor is too strong. 

When the skins have been removed from the liquor, 
the clear portion is reserved for a new dressing, for which 
purpose it must be treated with a complement stronger 
than the first. This acid liquor facilitates the fermen- 
tation of the new composition, which sours rapidly. In 
this manner the white dressings are in train, and may be 
kept at one-half the expense of flour, time, and money. 

After the hides are taken out of the dressings, they 
are left to drain on the cover ; and, when cooled, they 
are soaked in water a few moments ; in order to eflect 
the removal of a viscous coating derived from the barley, 
they are drained anew. 

Now they are submitted to the red dressing, which 
prepares them for the tanning. To prepare this dressing, 
charge the tub with about forty pounds of crushed bark. 



WALLACHIA LEATHER. 225 

which is mixed in water, then place the hides in this 
mixture. Take them out at noon, allow them to drain 
seven or eight minutes, and again in the evening for a 
quarter of an hour. Before putting them back the last 
time, treat the liquor with forty pounds of crushed bark, 
thoroughly stirred. The mornings of the second and 
third days, add twenty-four pounds of bark, take out the 
hides daily, and every time drain for half an hour. The 
fourth day take them out only twice, morning and 
evening; add no bark, and allow forty-five minutes to 
drain. The fifth day take out the hides in the morning, 
drain, and stir the liquor thoroughly; return the hides 
to the tub, hair side uppermost. Throw some handfuls 
of bark between each skin, and on the top of the last 
one, which should have its flesh side uppermost. Leave 
the hides eight or ten days, remove, rinse, and put them 
into the vats. 

Bran Dressing. 

According to some tanners, the red dressings may be 
omitted, if the white dressings are nflade with bran, but 
the opinion of the majority of tanners is in favor of 
red dressing. However, we shall say a few words about 
the method employed. 

The bran dressings are made either cold or hot. For 
the first, a leaven is prepared with yeast, or made with 
one and a half pounds of wheat or rye flour for each 
hide, and kept at a moderate temperature. The skins 
are freed from all adhering dirt which soils them; they 
are then fleshed and dipped. Boil a quantity of water, 
sufiicient for a bath for all the skins, with bran, seven 
or eight pounds for each skin. Cover the boiler, and 
when the liquor has sufficiently fermented, pour it into 
15 



226 . TANNING. 

a vat in which the skins, previously rinsed, have been 
deposited. 

While the skins are getting warm, heat another quan- 
tity of water till it simmers, and mix it with the ferment 
made at the beginning of the operation. Take the skins 
out of the bath, pour the fresh mixture into the vat, 
mix with it salt in the proportion of a little more than 
a pound for each skin, stir, and deposit the hides in it. 
Six hours after withdrawing the skins replace them, 
after a portion of the liquid has been previously taken 
out, heated, and well mixed with the contents of the vat. 
Kepeat this operation every six hours during the two 
succeeding days. As soon as the hair is ready to come 
off, remove it from the surface ; then the skins are 
passed over lightly upon the jflesh, soak them in cold 
water for a quarter of an hour, replace them in the vat, 
and leave them until sufficiently raised, being careful to 
keep the vat perfectly covered so as to retain the heat. 
The raising is generally completed at the end of three 
days, if a portion of the liquor in the vat has been re- 
heated from time to time. 

Rinse the skins, and let them soak for some hours in 
fresh water. Remove the hair where it is ready to be 
(detached, rinse the skins, pass lightly over the flesh 
«ide, soak some hours in water, and deposit them again 
Mi. the vat in order to raise them. 

This method is very convenient for tanners who 
manufacture on a small scale, as it is inexpensive. 

Decomposition of the White Dressings. 

These dressings are sour pastes of barley, rye, or 
wheat, which, under certain circumstances, undergo a 
decomposition, and it is believed that lightning produces 
this effect. Some tanners place in the vat scraps of old 



RYE DRESSING OR TRANSYLVANIA LEATHER. 227 

iron enveloped in linen rags upon the approach of a 
thunder storm ; while others dissolve from one-half to 
one pound of sal ammoniac in the vats, under the belief 
that these substances prevent the injurious consequences 
of the turning of the liquors. When the dressings expe- 
rience this kind of decomposition, they are unfit for anj 
further use, and render the skin so soft and spongy that 
the quality of the leather would be impaired. 

The long continuance of the heat of the summer 
causes this decomposition, and the quality of the dress- 
ings is more likely to be injured in the three summer 
months than in all the rest of the year. 

Cold has no influence upon them, it only diminishes 
their efficacy ; and the skins may be allowed to remain 
in them even when the surface is frozen, if afterwards 
they are replaced in fresh dressings. 



CHAPTER XXXII. 

EYE DRESSING, OE TEANSYLYANIA LEATHEE. 

The Transylvanians work their hides about the same 
way as Wallachians. Their method differs only in this, 
the latter use 20 lbs. of barley while the former use only 
15 lbs. of YjQ, which they divide into two portions. It 
enters 10 lbs. in the first composition, and eight in the 
second. As the grounds of rye keep their strength and 
quality longer than those of barley, on account of the 
gluten they contain, they are not thrown away, but are 
used even after decantation of the sour liquor, which 
renders this process less costly than the other. 

We have given the above processes to satisfy manu- 
facturers, rather than to induce them to use them; 



228 TANNING. 

for the dressings with barley, and generally with grains, 
are not followed now, on account of the influence of the 
temperature on them. The process described in the 
following Chapter is the most used now. 



CHAPTER XXXIII. 

EAISING BY SOUR TAN LIQUOR. 

This method was first practised in Germany, but has 
since been adopted in many parts of France. 

This process is the most difficult, but is very advan- 
tageous, as it is the beginning of the main tanning ope- 
rations, and serves to abridge the time occupied by them, 
and the leather prepared by it is of much superior 
quality to that treated by lime, barley, or rye. We 
shall describe this process minutely and fully, commenc- 
ing with the account of those originally employed. 

The first is by Champion. When this method was 
first employed in France the depilation was efiected by 
the action of heat; and to prevent the putrefaction, from 
one pound to one pound and a half of salt was sprinkled 
over one-half of the surface of each skin— the other half 
being turned over upon it, and the edges brought to- 
gether so as to prevent the escape of the salt. From 
fifteen to twenty hides were salted in this manner, and 
placed one above the other, being left thus four or five 
hours in spring and autumn, and seven or eight in 
winter. At the eftd of this time the skins were folded 
again in the opposite direction, the bellies being placed 
upon the backs, and the heads under the tails, the whole 
being piled upon one another so as to be exposed equally 
to heat. The skins were first dried with the hair on, 



EAISING BY SOUR TAN LIQUOR. 229 

and were then soaked for eight days in running water, 
beaten with the feet or the mace, and again soaked dur- 
ing four to five days. They were beaten a second time, 
rinsed and drained upon the horse, after which they were 
salted as before described. After being freed from acid 
by the influence of heat, to which they were exposed in 
a tight vaulted apartment, they were soaked in running 
water. Then the skins were subjected to the steeping 
in sour tan liquor, which softens and enlarges the fibres, 
opens the pores, and raises them to receive the first 
tanning. 

Another method was to deprive the skins of hair by 
stacking them on heaps, as represented below, and pro- 




moting warmth by covering them with straw or manure, 
until the hair is ready to be removed. If it comes 
off with difficulty upon the horse, its separation is facili- 
tated by the use of sand spread upon the hair side. 
This method is disadvantageous, and injurious to the 
skins. 

To prepare the tan liquor for the bath, the bark which 
has been used for the second or third set of vats, in the 
tan-yard, is deposited in a vat thus arranged that the 
liquor percolating through it may be received in a drain- 
ing-well or vessel placed under it ; from which it can be 
returned into the main receptacle again and again, so 
as to secure an increase of strength by repeated filtra- 



230 TANNING. 

tions and solutions. This liquor has a clear red color, 
an acid taste like that of good vinegar, and from this 
solution a number of baths can be made of different 
strengths. A series of eight baths may be made, the 
first one containing one part of the liquor and seven of 
water, and so until the full strength is attained. When 
the skins are freed from hair, washed and fleshed, they 
are soaked two days in clear water, in summer, and four 
or five in winter, being careful to change the water 
every day, and to let the skins drain for three hours. 
When the skins are ready for raising, upon being 
steeped, they are deposited in vats containing the in- 
fusion of spent tan, being first placed into the weakest. 
While remaining in these, they are taken out every 
morning and evening, and allowed to drain over the vats 
during three hours. Towards the end of the proceeding, 
when in stronger infusions, a removal of the vats once 
a day is sufficient. 

The English tanners use baths with less acid than 
those employed in France ; they are infusions of fresh 
bark in water. They use a large number of baths, in- 
creasing gradually in strength, and with vats of sufficient 
capacity for fifteen or twenty skins. 

From all the methods primitively used in France, the 
best is that followed at St. Germain, and thus described 
by Delalande : They generally employ twelve infusions, 
the two last being new, and the ten first consisting of old 
infusions of tan. Each bath is prepared for twelve 
skins. 

The skins having been scraped and washed, are de- 
posited in the first infusions, the weakest of all. It is 
necessary to have the bath a little acid. Twenty-four 
hours after, raise the twelve skins, let them drain half 
an hour, and introduce them into a stronger infusion ; 



RAISING BY SOUR TAN LIQUOR. 231 

throw away the water of the above, which, having been 
used ten times, has no more strength. 

The second infusion, while a little stronger, has no 
sensible acid action on the tongue; the third has a little 
more strength, and so forth. Every morning raise the 
twelve skins from one infusion to put them into another, 
until they have been treated in the ten vats. When taken 
out from the tenth infusion the skins are put into the 
first new infusion. This first infusion is composed of a 
sour water in which 20 lbs. of coarse tan are added for 
every skin. The skins stay ten days in this first infusion. 
At last the skins pass from this first infusion into an- 
other of the same nature, to which you add 20 lbs. of 
coarse tan for every skin. The skins stay ten days in this 
infusion, and then are ready to be tanned. An elevated 
temperature is injurious in the weakest infusions, and 
when' the operation is conducted in summer, be careful 
to not let the temperature raise too high. 

The sour liquor was prepared in the following manner; 
five ordinary vats being made use of: — 

The j^?-6-^, or No. 1, being destined for the weakest, and 
the last, or No. 5, for the strongest infusions. 

The spent tan from the pit in which skins had been 
imbedded for the third time was deposited in No. 5 and 
warm water poured upon it through a pipe or spout. 
The water filtering through the tan passed into a drain- 
ing well, and was pumped out after four or five days 
constituting an amount of tan-liquor sufficient for four 
of the ordinary weak vats. 

The pit was again filled with water, which after be- 
coming tan-liquor was transferred into the vats Nos. 1 
and 2, and the contents of Nos. 3 and 4 were composed 
of the liquors of Nos. 1 and 2; again it is passed through 
No. 5, and the infusion originally drawn from No. 5 was 



232 TANNING. 

replaced in it. The 11th and 12th vats, originally 
referred to, were made up from the contents of No. 5, and 
the other ten from the contents of Nos. 3 and 4 diluted 
in the proper manner with those of Nos. 1 and 2. 

The best tanners in France use now the following 
process : — 

The skins are carefully fleshed and deprived of all 
superfluous parts, and soaked for 24 hours in fresh 
water. When perfectly clean and well rinsed, they are 
deposited in the liquors by which they are to be depilated 
and raised. .These liquors are contained in a series of 
eight or ten vats made of oak, hooped with iron; they 
are 3 ft. 8 inches in depth, and 5 ft. 5 inches in diameter. 
In each vat deposit seven or eight skins, and cover them 
completely with the liquor. 

Let them soak 24 hours in the first vat, which con- 
tains the weakest liquor, and during that time' take 
them out twice to drain one hour, being placed on 
boards which are inclined so that the fluid dripping from 
them runs back into the vat. After two days, take them 
out, let them drain one hour, and place them in the second 
vat, which contains a stronger infusion. The same opera- 
tions are repeated daily until the skins have passed 
through all the vats. If at the end of this time the hair 
appears ready to fall off, it is removed from the skins by 
working them in the ordinary manner upon the horse 
with the round knife. In cold weather it is sometimes the 
case that the process has not been suflBciently completed 
at the end of the time mentioned, and that the skins 
require exposure to the strong liquors for five or ten days 
longer, in order that the hair may be removed with 
facility. 

The skins thus prepared have not yet been raised 
sufficiently to be tanned, and for this purpose must be 



RAISING BY SOUR TAN-LIQUOR. 233 

exposed to the influence of four more vats of tan-liquor 
gradually increasing in strength. The mode of operating 
is the same as described above. After having passed 
through these four vats, they are deposited in a vat of 
the size before mentioned, nearly full of strong fresh tan 
juice, which has been previously thoroughly mixed by 
repeatedly stirring with 4 lbs. 6 oz. of sulphuric acid of 
66°. During the first day of their soaking, the skins 
are taken out twice, and left to drain two hours ; on the 
second day they are removed twice, being allowed to 
drain the same length of time, and on the morning of 
the third day they are changed to the last vat, which 
contains the strongest tan-liquor that can be procured, 
previously mixed as before with 4 lbs. 6 oz. of sulphuric 
acid. On the evening take out, drain for an hour, and 
replace in the vat. The next day and the day after, 
take out again, drain the same length of time, and de- 
posite again in the liquor. Three hours after the last 
draining, they are finally removed and are ready for 
tanning. In cold weather the skins should be kept in 
the vats two days instead of one. The flesh side should 
always be placed upwards in the vats. 

Preparation of the Tan-Liquor. 

The tan-liquor used in the processes above described is 
obtained by the filtration of water through the partially 
exhausted bark of the second and third series of vats in 
the tan-yard, and derive from it their astringent and 
acid properties. This tan, after remaining for a time in 
contact with the skins in the vat, loses and gives up to 
them the greatest portion of its tanning ingredients, and 
then is readily disposed to ferment or acidify, still 
retaining some of its tanning properties, but becoming 
more and more acid as these are removed from it by 



234 TANNING. 

absorption into the tissues of the skins. These qualities 
are calculated to injure the leather and make its removal 
from the vats necessary before it has been too long ex- 
posed to the action of the exhausted and acidified tan. 

For the purpose of preparing the sour liquor, the tan 
is deposited in an empty vat in which a draining well 
composed of oak planks has been erected, as shown in 
the following figure. This well is so arranged that the 

Fig. 40. 




fluid can only enter it from below, and a pump adapted 
to it serves to withdraw its contents, or they may be 
removed in a bucket. The vat is then filled with water, 
and the solution formed by its filtration through the tan, 
is raised after a few days from the well, and is again 
poured over the surface. This proceeding is repeated 
over and over again until the tan is entirely exhausted 
of its soluble material. The top of the vat is kept close 
to avoid evaporation of the fluid. In place of this 
method the tan can be exhausted in the same manner 
as we have described in treating of tanning extracts. 

From fifteen to thirty days are usually required to 
give to the liquors the proper degree of strength and 
acidity. 

This operation can be done only in large establish- 
ments; however, with few vats only it is easy to make <% 
tanning juice ; the following is the best method : Put the 
old bark into two vats that you fill with water after 



EAISING BY SOUR TAN-LIQUOR. 235 

three or four weeks of maceration, make in the middle 
of the vat a hole large enough to introduce a pail, draw 
the juice and pour it back on the same vat, where it 
stays five days more, repeat the same operation until the 
juice has the required strength. Pass it through a sieve 
to have it clear. 

This juice being withdrawn, pour some new water, 
leave eight days, and draw. The juice is weaker. For 
the depilation and swelling three vats and five solutions 
are sufficient. The first solution is very weak, and its 
strength increases progressively. Proceed as follows : 
Make a new solution, composed of pure water, or better, 
very weak juice, in which you put four baskets of tan. 
Introduce the skins, beat them, raise them three times 
a day, morning, noon, and night, and every time leave 
them to drain one-quarter of an hour; draw off the 
liquor. 

The second day, put the skins in a weak solution 
composed of three-quarters water and one-quarter juice, 
with six baskets of tan, raise three times during the day, 
leave to drain one-quarter of an hour each time, and 
throw away the liquor. Introduce the skins in another 
solution composed of one-half juice, one-half water, and 
six baskets of tan, as shown in Figure 41. Leave two 

Fig. 41. 




days, raising three times a day, being careful to let drain 
half an hour. 

The fourth solution, formed of the clear juice of the 



236 TANNING. 

above, lasts twenty-six days. The first day introduce 
the skins in the morning, and for six skins add thirty- 
six pounds of bark. The second and third, add in the 
morning twenty pounds of the same bark. During 
these three days, raise three times a day, leave to drain 
half an hour every time. The fourth day add twenty 
pounds of bark, and raise twice. The fifth, raise, leave 
to drain half an hour, stir, add forty pounds of bark, and 
leave eight or nine days without moving. After nine 
days pass in the last solution or pure juice, raise twice 
a day for three days, add twenty-one pounds of bark in 
the morning. The fourth day raise, leave to drain three- 
quarters of an hour, and put the skins back, being care- 
ful to throw between each four, eight pounds of bark. 
Leave eight days, and then the skins are ready to be 
tanned. 

This process can be used by small tanners, and to 
terminate the swelling you can put sulphuric acid in the 
two last solutions, but instead of eight or nine days leave 
the skins only three days. 



CHAPTER XXXIV. 

EAISTNG BY YEAST. 

Yeast has the property of raising skins, and has 
been used for this purpose. It is mixed in a vat with 
warm water, the vat is covered, and fermentation takes 
place. When this is fully established, a quantity of salt 
is thrown in, and the skins are deposited in the vat, the 
contents of which are then treated precisely as in the 
case of barley dressing. The operation can be conducted 
in the cold, but is much more rapid and successful if 
the temperature of the liquor be kept elevated. 



WORKING ON" THE BEAM. 237 



CHAPTER XXXV. 

WORKING ON THE BEAM. 

After the skii^ have been prepared for the separation 
of the hair upon them by any one of the numerous pro- 
cesses which have been described, the next proceeding 
is to remove it entirely by working them upon the beam. 
For this purpose the workman makes a kind of pad of 
two or three folded skins, which he places upon the 
horse, and over which the skin to be operated upon is 
laid with the hair side up, and he then scrapes the sur- 
face strongly from above downwards with the scraper. 
After the hair is completely removed the skin is washed 
and soaked in a trough, or vat full of water, and is sub- 
jected to the following operations : — 

1. The flesh and other parts not properly belonging 
to the skin are removed with a sharp knife called the 
flesher, and the skin is again washed and soaked in fresh 

water. 

2. The projecting filaments or shreds, and those parts 
of the borders of the skin which are thicker than the 
rest, are cut off with a sharp knife, and the skin is again 
immersed in cold water. The portions thus removed 
may be set aside to manufacture glue. 

3. The hair side is then well rubbed and smoothed 
down with a stone, similar to that used for sharpening 
the knife-blades, but which is set in a wooden handle. 
This done, the skin is dipped for the third time in fresh 
water. 



238 TANNING. 

4. Both sides are well scraped and smoothed with a 
knife having a curved l)lade, so as to equalize the sur- 
faces and remove all foreign substances. 

A dozen skins can be worked in this way by one man 
in the course of a day. 



TAN VATS. 239 



SECTION Y. 

TANNING PROCESS. 

Having completed the consideration of the various 
operations to which skins are subjected before they are 
prepared for tanning, we proceed to give an account of 
the latter process, beginning with a description of the 
vats in which it is conducted. 



CHAPTER XXXVI. 

TAN YATS. 

That name is given to large square holes excavated 
in the ground, or to large vats in oak with a circular 
form. The first are still in use in several countries; 
they are seven and a half feet square by six feet deep. 
They are in masonry, and covered inside with a kind of 
mortar made with lime, sand, and cement. In Paris 
they use oak vats of a round form and sunk into the 
ground. The latter are preferred to the first, and are 
not subject to the same inconveniences. 

1. Whatever care is taken, those in masonry always 
lose some of the infusion. 

2. The lime of the cement combines w^th the tannin, 
and forms an insoluble tannate of lime. 

3. The vats in oak wood, carefully made, do not lose 
any liquid. 



240 TANNING. 

4. Oak wood, instead of neutralizing a part of the 
tannin, furnishes to the liquor a new quantity of tannin. 

These facts should induce all manufacturers to use 
them. 

All tanners do not operate in the same manner. We 
shall be careful to indicate all the little changes they 
have made in the common process. 

After the skins have undergone all the preliminary 
operations, they are cut in two, and stratified along with 
tan in the following manner : — 

In the bottom of the vat put a bed of spent bark, 
about half an inch thick, cover it with about a quarter of 
an inch of new bark, well moistened, and place a skin on 
the top. In square vats, put two hides in one way and 
two in another, and set acr9ss them a fifth one ; but in 
circular vats lay the hides all round, then be careful 
to turn exactly at the right, and fix them so that the 
tail of the last rests on the right leg of the preceding. 
By following this process a vat containing fifteen ot six- 
teen skins can be filled in twelve hours. 

On the first layer of skin spread another bed of pow- 
der, and continue thus by laying alternately a bed of 
powder and one of skin. Be careful to have powder 
between every part of the skin, for if it has none the 
skin will not be equally tanned, and consequently will 
not be equally strong and solid. Some thicker places 
require more bark, but the shoulders and legs, being 
thinner, require less. 

In Paris all tanners moisten the bark before using 
it. For this purpose they throw water upon it and mix 
it thoroughly with a shovel, then it can be divided more 
easily ; however, some manufacturers use it just as it 
comes from the mill. The Parisian method is the best, 
as it is not injurious to the health of the men, who by 
using dry po\Vdered bark are exposed to its inhalation. 



TAN VATS. 241 

In speaking of the tan, we have said that the English 
cracked the bark; several tanners have adopted this 
process, but it is not followed everywhere. It is gene- 
rally admitted that the first ought to be fine, the second 
a little coarser, and the third very coarsely ground. 

When all the skins are laid in the vat, it may happen 
that the vat is not entirely full, and, whilst the skins 
have been uniformly put up, some empty spaces are 
found, they are filled with powder; or rather when you 
have put in a sufficient quantity of new powder, distri- 
bute it so that the surface is equal all over. 

In small tanneries, the pits are not always filled on 
the same day, and frequently only a small number' of 
hides are placed in them at a time. As it is essential in 
these cases that they should be kept fully moistened^ 
more water should be added each time that the new 
skins are deposited in them; and in order that the rela- 
tive position of the contents may not be disturbed, the 
surface should be covered with a coarse cloth, and the 
water carefully poured over from a watering pot, and 
allowed to infiltrate gradually. 

The water being equally distributed through, and in 
sufficient quantity, the vatting of the pit is completed. 
In establishments where they do not commence vatting 
until a number of hides sufficient to fill the vats has been 
prepared, the watering should be completed in one oper- 
ation. When this is the case, it may happen that the 
tan rapidly absorbs all the water poured in, and in a day 
or two appears perfectly dry. More water should thea 
be added, until it is certain that the vat contains enough 
to moisten all the hides thoroughly. The quantity re- 
quired for each hide is about 12 gallons. 

AVhen, as often happens, particularly in small estab- 
lishments, the tanner is compelled to place together in 
16 



242 TANNING. 

the same vat, hides in different states of progress, that 
is, those of the first, second, and third treatment, the 
following mode of arranging them must be resorted to. 
Those of the third treatment are to be deposited at the 
bottom, those of the second above them in the middle, 
and those of the first on top ; so that, when those which 
have gone through the three treatments are taken out to 
dry, those of the second may occupy their place at the 
bottom, those which were before at the surface being in 
the middle, and the fresh hides which are to be subjected 
to the first treatment being placed at the top. This 
convenient method promotes an equalization of the tan- 
ning, and should always be adopted ; because the con- 
tinued exposure of the same set of hides to those parts 
of the vats which possess the greatest tanning power, and 
of others to the upper strata of bark which contains the 
least, is thus avoided. The substances at the bottom of 
the vat, undoubtedly, are those which possess the strong- 
est tanning power, because the descending infusion, pass- 
ing through the layers of tan above, becomes more fully 
impregnated with tannin and extractive matter than 
that portion which remains in contact with the upper 
strata of the solid materials. Moreover, the complete 
penetration and combination of these matters with the 
fibrine and gelatine of the skins is promoted by the pres- 
Bure of the superincumbent hides, the tan, and the 
column of fluid. 

When the ordinary arrangement is adopted, it is cus- 
tomary, in filling the second vat, to place at its bottom 
those hides which have been at the top of the first, and 
fio on through the ranges of vats. This is done for the 
purpose of promoting a uniform impregnation of all the 
hides; since, if always kept in the same position in their 



TAN VATS. 243 

progress througli the yard, those occupying the lowest 
one would be the most thoroughly charged with tannin. 

As oak bark is variable in quality, it is scarcely possi- 
ble to give, with certainty, any proportion which it 
should bear to the^kins. Skins weighing 110 lbs. usually 
require, however, about double that amount of bark. 
From 33 to 44 lbs. usually suffice for each of the skins 
from Brescia, which do not commonly weigh more than 
26 lbs. Weak, thin and poor, or d%y hides, being of infe- 
rior quality, require very little bark, and scarcely acquire 
any increase of substance. Common hides scarcely ever 
need exposure to more than three treatments, the first 
being given upon the grain, and the others upon the flesh 
sides. The finest powder is used for the first process, 
which should occupy three months. Coarser stuff is em- 
ployed for the second, which should take four months, 
while the coarse bark alone is sufficient for the third ex- 
posure, occupying five months. This length of time may 
be considered sufficient for tanning, though the best tan- 
ners extend it, giving to their hides four, or for the best 
qualities, even five exposures in the pit. 

Fresh hides exhaust the tanning ingredients to which 
they are exposed in the first process, much more rapidly 
than they do in the subsequent ones; and hence the neces- 
sity of a longer treatment in the second and third vats 
than in the first. After they have been thoroughly fed 
in the first, further contact with the spent materials 
would be useless, as these are almost entirely deprived 
of activity ; and it may be very injurious to them by pro- 
moting putrefaction. In passing through the last vats, 
however, they run no such risks, for being in contact 
with strong solutions of bark, they are still constantly — 
though from the resistance of their already tanned sur- 
face gradually — absorbing tannin and acquiring density. 



244 TANNING. 

Small portions of alum are added to the tan by some 
manufacturers, with the intention of diminishing the 
impermeability of these tanned surfaces, and hastening 
the process in its latter stage. The practice is, however, 
neither a common nor a desirable one* 

In changing hides from one pit to another, be careful 
to remove from their surfaces all the spent tan which 
covers them, so that there may be no mixture of effete 
matter with the frei^ bark. Some tanners even take 
the trouble of beating and shaking the hides each time 
they are changed. 

There is another form of vat, recently invented, and 
patented by J. S. Wheat, of Wheeling, Va., who makes 
the following statement : — 

"1 have my tanning process in full operation in this 
city, tanning leather in -^^ of the time required by the 
old process, and I warrant the leather to be of the finest 
quality for wear. This process combines the handling or 
moving of the hides in the liquor, the circulation of the 
liquor through the vats, the pressure upon the hides, and 
the circulation of the liquor through the tan bark in the 
leaches, all at the same operation, and the operation 
may be suspended upon one or more of the vats while it 
is continued in the others. Therefore amongst its advan- 
tages, in addition to the short time consumed in tanning 
leather, is the great saving of labor." 

Fig. 42 is a perspective view of the apparatus, and 
Fig. 43 is a horizontal section through the middle of the 
vats combined with a horizontal section through the 
several reservoirs. 

The leather is placed in the air-tight cylindrical vats 
X,X",X"',X"", and the tanning liquor which is prepared 
by mixing water with bark in the rectangular reservoirs 
E",E"',E"",E""', below, is made to circulate through the 



245 




Fig. 43. 




vats by means of a force pump C. The liquor in the 
vat is subjected to pressure regulated by a weighed 
valve, and the hides are forced through the liquor by 
being placed on vibrating frames K (Fig. 43) within the 
vats. 

The water is mixed with the bark in the reservoirs 
E'\E"',E"",E""', and these reservoirs have perforated 
false bottoms through which the clear liquor is strained 
into the lower parts of the reservoirs. 

From these places it is drawn out by means of the 



246 TANNING. 

pump, through branches from the pipe A, which pass 
through the ends of the reservoirs, and are bent down 
so as to extend through the false bottoms into the clear 
liquor below. These branch-pipes are provided with 
stopcocks, so that the connection between any one of 
them and the pump may be opened or cut off at will, 
and thus the liquor may be drawn from such of the re- 
servoirs as the operator may desire. 

From the pump the liquor is forced into the vats 
through the pipe D, which has two branches leading 
into the bottoms of the vats X,X". From the top of 
vat X a pipe D' leads to the bottom of vat X", and a 
pipe F leads to the bottom of vat X". The pipe D'" 
leads from the top of vat X" to the bottom of vat X", 
and the pipe F" leads from the top of vat X" to the bot- 
tom of vat X"". A pipe D"" leads from the top of vat 
X" to the pipe F"', which is connected with the top of 
vat X"". All of these pipes are furnished with stop- 
cocks, so that any vat may be thrown out of the circula- 
tion by simply opening and closing the proper cocks. 

From the upper end of pipe F'" a pipe D"" leads down 
to the reservoirs, with all of which it is connected by 
branch-pipes ; each branch being furnished with a stop- 
cock. 

It will thus be seen that the tanning liquid is kept in 
constant circulation through the vats containing the 
hides, and through the reservoirs containing the bark ; 
extracting in its course the tannin from the bark and 
carrying it to the hides. The liquor in its ascent 
may be passed through such of the vats and reservoirs 
as the operator may desire by simply turning stopcocks. 

In the upper end of the pipe F'", but below the exit 
of pipe D"'", is a valve which is pressed down by a weight 
upon the lever N. By setting this weight at the proper 



heald's apparatus for tanning hides. 247 

point upon the lever, the pressure of the liquor within 
the vats may be adjusted to any desired degree. An 
emptying pipe G, connected with the bottoms of all the 
vats by branch-pipes, leads into the reservoirs E. 

The frames H, in the vats, are hung upon shafts, 
which pass through stuffing-boxes in the ends of the vats, 
and they receive a vibratory motion from eccentrics on 
the pump-shaft, with which they are connected by levers 
in such a manner that by simply lifting the levers out 
of connection the action of the frame in any vat may be 
suspended. The hides are introduced into the vats 
through manholes provided for the purpose. 



CHAPTER XXXYII. 

HEALD'S APPARATUS FOR TANNING HIDES. 

Wm. H. Heald, of Baltimore, invented and patented, 
in 1860, an apparatus for tanning hides. We give below 
a description of its construction and operation. The 
Fig. 44 represents a perspective view of said apparatus. 

Figure 45 represents a longitudinal vertical section 
through the same. 

The work of repeatedly raising the hides from the 
vat, for the purpose of exposing them to the air, consti- 
tutes one of the most laborious tasks in the operation of 
tanning. This invention relates to the construction of 
an apparatus to which the hides are united in such a 
manner that they will hang loosely and vertically in the 
vat, and may be raised from the vat with facility, and, 
Avhen raised, lie in a pile, and the drippings therefrom 
all run back into the vat. 



248 



TANNING. 



To enable others skilled in the art to make and use 
this invention, we shall proceed to describe its construc- 
tion and operation. 

Fig. 44. 




A represents the vat which contains the tan-liquor. 
B represents a triangular frame, which is suspended 
within said vat by means of ropes or chains, C, and which 
can be raised or lowered by turning the crank D, and 
the drums E, around which the ropes or chains, C, are 
wound. The frame 5 has grooves, a, cut on its inner 



heald's apparatus for tanning hides. 249 

sides, into which the ends of the bars h are inserted. 
The hides, c, to be tanned are hung over these bars, as 
represented in Fig. 45, and one or more such grooves 

Fig. 45. 




may be used for securing the bars therein. When three 
such grooves are used, the hides may be suspended, as 
represented in Fig. 45, where the bar of each consecu- 
tive hide is inserted in a different groove, by which 
arrangement they can be inserted and removed with 
greater facihty than when they are all inserted in one 
groove, and when they are packed closely together. 
The frame, B, has pivots, g, at its side, which slide in 



250 TANNING. 

corresponding grooves, li, in the sides of the vat, and 
which cause the frame to move perpendicularly on being 
raised or lowered. When the frame is to be raised for 
the purpose of exposing the hides to the air, or for re- 
moving them, the crank D is turned and the frame B 
rises, and as the side near the pivots, g, is somewhat 
heavier than its opposite side, the frame will lean to- 
wards that side, and when arrived at the top of the vat, 
it will be raised on the edge of the side of the vat, as 
represented in a, h, Fig. 45, and may then be raised 
to any degree of inclination, or almost to a horizontal 
position, leaving just sufficient inclination for the drip- 
pings to run back into the vat. The frame in this posi- 
tion may be secured by braces, stops, or their equiva- 
lents. To prevent the frame from being raised out of 
the groove, h, by inadvertence, the stop pins, m, may be 
used, by which the motion of the frame is arrested as 
soori as the pivots, g, come in contact with them. By 
this apparatus the hides, when once hung within the 
frame J5, do not require any further handling, and can 
be raised and lowered with facility, thus saving a great 
amount of labor in the operation of tanning ; and when 
frame B arrives at the position shown in Fig. 44 the 
hides lie on top of each other in a pile, and may be 
conveniently removed. In this position, too, the frame is 
more readily filled with hides, as it is comparatively 
clear of the vat, though ready to turn into it when de- 
sired. In the mere handling of the hides these machines 
save much labor, as they can be immersed in the vat or 
raised out again into a pile, whence they can be removed 
and others put in their place. 

From the time the hides are placed in the frames 
until they are ready to be laid away in bark, is six weeks, 
thus saving four or five weeks over the old style of reels. 



TIME NECESSARY FOR TANNING. ' 251 



CHAPTER XXXVIII. 

TIME NECESSARY FOR TANNING. 

The importance of discovering some process which 
should shorten the time usually occupied in tanning, 
without injuring the beauty and durability of the lea- 
ther, and which should also diminish the expense of the 
manufacture, by substituting some less costly materials 
for oak bark, has long been appreciated by chemists and 
practical men. 

Among others, who have devoted much attention to 
this subject, is Seguin, who, acting upon his opinion that 
the combination of tannin with the gelatine and fibrine 
of skins might be much accelerated by presenting it to 
them in a liquid and concentrated form, succeeded in 
greatly shortening the time required for tanning. But 
experience has shown that, though the leather prepared 
by such means is, to all appearances, well tanned, it does 
not possess the requisite quantities. It is not thoroughly 
and uniformly impregnated ; for, while the outer layers 
of the two surfaces combine rapidly with tannin, a de- 
posit of gallic acid and extractive matter forms a compact 
coating, which prevents their complete penetration, and 
renders their interior inaccessible to the liquid. This 
leather is dry, and by no means durable, its interior con- 
sisting of untanned hides. We shall speak of it in treat- 
ing of Seguin's process. 

Experience has shown that, to insure the perfection of 
leather, all the gelatine and fibrine of the original skins 
must be made to combine with tannin, and that this 



252 ' TANNING. 

combination must be effected in the most gradual way, 
the accomplishment of which is only to be procured by 
exposures to solutions, which at first are weak, and after- 
wards are increased in strength, until at last complete 
saturation is arrived at. After this entire conversion of 
substance has been attained, further exposure only serves 
to injure the texture of the hide by introducing into it a 
dry, hard, and horny matter, which renders them brittle 
and easily penetrable by moisture, and to consume use- 
lessly the time and money of the manufacturer. 

If, on the contrary, they have been exposed too short 
a time, they will be imperfect and wanting in the requi- 
site weight and solidity. It is therefore an established 
fact that 12 or 18 months are required for the complete 
tanning of the best qualities of hides, they being found 
to increase in strength and weight up to the end of that 
time, which is the usual duration of the process in Eng- 
land as well as in this country. Still there, as well as 
here, skins are often sent into the market after an ex- 
posure of six or ten months, and even less. 



CHAPTER XXXIX. 

PEOPOETIONS OF THE BAEK USED. 

The proportions of bark required vary considerably, 
according to the species, the quality and destination of 
the hides. For the skins of the butchers in Paris, weigh- 
ing 112 lbs., at times from 336 to 393 lbs. of tan are 
used. Sometimes 292 lbs. divided into 4 parts are suffi- 
cient, 90 for the first, and 67 for the others. 

In the provinces of France they vary much in weight. 
At Bordeaux the liquors are strong, while in Brittany 



DRYING OF THE LEATHER. 253 

they are weak. In some places they do not use less 
than 675 lbs. of bark for 225 lbs. of fresh skin, the 
weight of which after tanning has increased to 337 
pounds. 



CHAPTER XL. 

DRYING OP THE LEATHER. 

The drying of the leather, however simple a process 
it may appear, requires the utmost skill and attention 
on the part of the workmen, and the nicest determination 
of the point to which it should be carried. Skins dried 
too slowly, and in moist situations, are liable to mould, 
which is greatly to their injury, while those which are 
dried too rapidly, or during exposure to the direct rays 
of the sun, become hard and brittle. 

In order to prevent either of these extremes, every 
factory should have attached to it a drying-room pro- 
portioned to its wants, in which numerous openings or 
windows admit a free current of air, while the leather is 
protected from the direct influence of solar heat. 

The skins, when sufficiently tanned, are to be taken 
from the pits without being shaken or beaten, and are 
to be stretched on pegs or hu^g up by their heads from 
large nails, each one being kept expanded by two or three 
sticks passed through from side to side, so that all parts 
may be uniformly exposed to the air. When they have 
begun to whiten and have become slightly stiff, but 
before they are perfectly dry, they are stretched out 
upon a clean place and scoured with the spent tan with 
which they are still covered. When well cleaned in 
this way, they are then to be trod out and beaten with 



254 TANNING. 

the soles of the feet in every direction, upon both sides ; 
and after the inequalities and protuberances of surface 
have been made to disappear by this flattening process, 
they are assorted in sizes and piled up in heaps. 

While the skins are stretched in the drying-room, 
they should be beaten twice daily, at morning and eve- 
ning, upon the flesh side with a round-face wooden mal- 
let. If the skins should be dry, the operation may be 
facilitated by moistening their surface with a wet brush. 
This process imparts firmness. 

The Shoe and Leather Reporter has lately published a 
very good article on the drying of tanned leather, an 
extract of which we think will interest the reader. 

"To overcome difficulties, we must first appreciate 
them. The difficulties and delays in drying leather as 
above described are very great. The amount of leather 
which tanners require to have in the loft exposed to 
the risk of fire is always very large, and at particular 
seasons of the year so large that some find it difficult to 
obtain the requisite amount of insurance, even at a very 
high rate of premium. 

"We think it quite within our experience to state 
that a tannery turning out 150 sides per day must have 
exposed about 5,000 sides; which at 2 J per cent, would 
amount to $500 a year for the item of insurance. The 
loss of interest and inconyenience of delay must also be 
added, to appreciate fully the difficulties experienced 
under our present system. 

" We hope to be able to show that no tanner need have 
over 1000 sides exposed at any one time, to enable him 
to roll and furnish 150 or even 200 per day. This esti- 
mate, it will be perceived, would cover a first class tan- 
nery. 

" To make this improvement of practical value, it must 



DRYING OF THE LEATHER. 255 

be adapted to our present buildings. Bat if we describe 
a perfect drying loft, the features which are new will 
be appreciated, and may be applied to each tanner as 
his circumstances may permit. 

"The building should be as high as possible, not cer- 
tainly less than twenty, and if fifty feet from the base 
floor to the peak, all the better. 

" The lower floor should be closed against the dampness 
of the yard, or if placed on the ground, from the mois- 
ture which would arise. No opening or window should 
be allowed except from the lower part immediately over 
the base floor, and this opening should be by a hoard trap 
opening, say of one foot wide, so hung on hinges as to 
be easily regulated, and should extend all around the 
building. The other opening should be in the extreme 
peak of the building, and should also be so constructed 
as to be easily opened and closed. . A drying loft thus 
constructed will always, by its own action, have a draft 
passing through it, even when the outside weather would 
indicate that there was no air stirring. 

"In ordinary drying weather such a loft will dry wet 
leather from the vats in five or six days. But this will 
not of itself accomplish what we want. We must have 
some artificial means of drying when the weather is not 
favorable. 

"This artificial heat can in no way, in our judgment, so 
satisfactorily be applied as by steam pipes. These are 
the best distributors of heat of any that have yet been 
applied. 

"Heat or dry air can be forced by blowers into a loft, 
but to do this effectually considerable power is required. 
Steam pipes, when properly laid, are self-acting, and dis- 
tribute heat more gently and uniformly than stoves, 
however placed. 



256 TANNING. 

"Some of the conditions to be observed are the follow- 
ing: The boiler which generates the steam must be lower 
than the base floor. The opening from which the escape 
steam pipe should enter should be from the top of the 
boiler, and the return pipe should enter at the bottom ; 
when thus placed, there will be none of that bursting of 
pipe of which we hear so much. 

*' The pipe should be as nearly as possible on a level or 
incline towards the boiler, so that the condensed steam 
or water will run freely in that direction, but where 
eight or ten pounds of steam pressure is kept on the 
boiler, little difficulty need be apprehended. It is only 
when there is no pressure of steam that the water freezes 
in the pipe and gives trouble. 

" But we omit practical details, since no tanner will at- 
tempt to adopt this improvement without consulting a 
practical pipe fitter, and they are now to be found in 
most every town. ^ 

"Experience has indicated that about five thousand feet 
of pipes properly laid will do all the drying that any 
ordinary tanner will require at eight pounds pressure. 
This pipe should be laid on the floor as near the centre 
as possible, and not around the sides of the building, as 
some have placed it. The pipe to be covered with lat- 
tice wood work to prevent disturbance. 

"Experience may show that the side may be the proper 
place to fasten the pipe if placed opposite and inside the 
opening of which we have spoken ; for the current of 
air from the outside may be sufficiently strong to force 
the heated or dry air to the centre, and thus form a cur- 
rent up to the top opening. But we are sure without 
such opening the air forms a current up the side of the 
building, and does not penetrate the centre. 

"The eflectof side openings, other than the kind here 



BEATING OF THE LEATHER. 257 

recommended, is to create counter currents and destroy' 
the whole effect. 

*• This whole subject is both new and interesting. We 
do not think there is any novelty in the use of steam 
pipes in drying lofts. But we think that most of the 
effect has been lost heretofore by reason of the improper 
construction of the loft. 

" We think that a tanner may run partitions inclosing 
three or four bents of his tannery, from base floor to the 
peak, and dry more leather in these few bents than he 
does now in his whole loft. 

" With a proper heating apparatus in connection with 
a properly constructed drying loft, sole-leather wet from 
the vats can be dried in forty-eight hours, ready for the 
roller." 



CHAPTER XLI. 

BEATING OF THE LEATHER. 

After the skins have remained in pile for a day, they 
are exposed to the air, as before, for four days. When 
nearly dry, they are taken down and pressed under 
planks heavily loaded with large stones. The next 
day they are spread out upon an oak or marble table 
and beaten with an iron mallet, so as to compress their 
tissue and render them smooth and compact. The 
operation is performed as shown in the figure. 

This proceeding should never be omitted, whatever 

may have been the original preparation of the skins for 

the vat. Lime hides should, however, be treated before 

they are dried, as otherwise the hair side surface would 

17 



258 



TANNING. 



be exposed to the danger of being broken and rendered 
uneven. 

Fig. 46. 




The process of beating leather is essential to give it 
firmness and durability, and to make it impervious to 
moisture. It is only the first step of the manipulation 
which the shoemaker finds it so necessary to continue 
upon the lapstone. 

The leather, after being thus hammered, is now tho- 
roughly dried for the last time, and piled up in a dry 
and well-ventilated loft. Before it is ready for market, 
the leather should be repeatedly shuffled, as it were ; 
that is, the position of each hide must be changed, and 
the piles spread out in the manner of an open fan, and 
pressed as before, under planks and superincumbent 
weights. 

Having undergone these different processes for nearly 
a month, it is again piled preparatory to being sent into 
the market. Not satisfied with this management of it, 
some tanners even take the unnecessary trouble of stor- 
ing it away in cellars for some time before they consider 
it thoroughly seasoned. 



BEATING AND ROLLING BY MACHINERY. 259 



CHAPTER XLII. 

BEATING AND ROLLING BY MACHINERY. 

The process described above was a tedious and labo- 
rious mode of operating, which is rarely resorted to now, 
and has been superseded by machinery. The principal 
object of these machines was to accelerate the process 
and diminish the labor, and afterwards it was found that 
they also accomplished the desiderata of imparting 
smoothness, compactness, and uniform thickness to the 
leather. 

In the earlier stages of this invention the imperfection 
of the machinery rendered it necessary to finish the 
beating by hand, but improvement grew with experience 
and has resulted in some perfect apparatus. 

Sterlingue & Co. were the pioneers in this branch of 
ingenuity, and proposed the use of a hammer like those 
employed for forging iron, but grooved, and an anvil 
faced with brass. The other portions of their machine 
are a table for receiving the hides and cylinders for the 
cords or straps which kept the leather extended, their 
axes being connected with an endless chain in such a 
manner that the straps which are rolled upon them on 
one side are unrolled on the other. 

The hides are allowed to be at rest during the descent 
of the hammer, and are moved from under it during its 
elevatioj^. The blows may be increased in frequency 
and force at the will of the operator, and if it is thought 
proper to direct a number of blows upon one part of the 
hides, the movement can be suspended by a catch until 
the required number has been applied. 



260 



TANNING. 



Having found that the horizontal position of the ham- 
mer interfered somewhat with the motion of the hides, 
they substituted a vertical hammer, like a pile-driver. 
By this improvement they obtained the alternate and 
successive action of a number of hammers upon the 
leather, and established a system by which rows of 
hammers of moderate weight are so arranged that those 
of the second row descend upon the prolongation of a 
line oblique to that of the first one, and fall upon the 
hides with a constantly increasing force. 

Debergues Machine. — This machine, invented in 1840, 
is described in vol. Ivi. p. 40, plate 4, of French Reports 
of Expired Patents. 



Fiff. 4*7. 



/ ^.Jul\^-I.-^- ~-p »= 



7 




Figs. 47 and 48. 

«, a. Pulleys, for communicating movement. 



BEATING AND ROLLING BY MACHINERY. 



261 



h. Longitudinal iron shaft. 

c, c. Cast framework, supporting the shafts h and g. 

d, Cast support, for the end of the shaft h. 

e, e. Pinions, gearing with the wheels /, /. 

g. Iron shaft, carrying the wheels/,/, outside of the 
framework. 

Ji, h. Crank-rods, the iron pivots of which, ^, i, are 
fixed by means of nuts in grooves cut in the wheels// 
so that their position can be changed at pleasure. 

j. Iron shaft, receiving an oscillating motion from the 
cranks h and Ti. 

k. Cast-iron lever, carrying at its lower extremity a 
stamper or small cylinder in a fork, and having passing 
across it the shaft y, the movements of which it follows. 



Fig. 48. 




262 TANNING. 

The upper part of this lever is equally divided into 
two branches, in each of which is a groove traversed by 
the iron shaft w?, fixed at its extremities to double cast 
supports 01, n. Above these grooves there are two rests, 
o, o, for the cast-iron lever p, which pivots upon the 
trunnions q, g, and to the extremity of which is attached 
an iron rod which supports a cast box or iron plate, or 
else a wooden box which can be weighted if necessary. 
Upon the line marked by the rests, the lever can be 
moved over the whole space between the two supports, 
and this part should be accurately adjusted, so that, 
whatever may be its position, the lever will weigh uni- 
formly upon the rests, r. Iron shaft, adjusted between 
the two supports n, n, and resting at the other end upon 
a simple support s. The screw passes through the cast 
piece t, forming its nut, and having two projections 
pierced to receive the shaft m, upon which it moves 
when the screw is turned. As the projections of the 
nut t entirely fill the interval between the branches of 
the lever Jc, this lever must follow the movements of the 
nut exactly as if directly commanded by the screw, w, 
ti are two pulleys, across wliich passes the uncut part of 
the screw z. These pulleys are commanded by the other 
pulleys V, V, the one by a straight strap, the other by a 
crossed one, and are turned in an opposite direction to 
each other. 

X. Toothed shaft partaking of the rotatory motion of 
the main shaft, which, being traversed by a pin, but 
being movable to the right or left at pleasure, and fitting 
in the claws of the pulleys n, n, renders their movement 
uniform with that of the shaft. At the middle of this 
shaft there is a large groove, which receives two small 
iron stays, fixed to the interior of the oval which the 
lever y forms at its junction with the shaft. This lever 



BEATING AND ROLLING BY MACHINERY. 263 

is surmouDted by a ball tv, and is mounted upon an iron 
pivot, which is fixed upon the cross-piece a', fastened at 
its extremities to the supports n, n. 

h'. Round iron rod having a square part at the end 
which slides in one of its supports, and is, by this means, 
prevented from being turned. This rod passes across a 
tail-piece, attached to the nut t, and carries two rings, cf 
d, fastened at a convenient part by a compressing screw. 
The rod also has upon it two little projections, d' d\ 
which engage the lever ?/, and give it an alternate motion 
to the right or left, when the tail of the nut encounters 
alternately the rings d d. 

d. Cast, marble, or wooden table, surmounted by a 
copper plate. The table, as the plan shows, may be 
either plane or concave, without any injury to the suc- 
cess of the process following.* 

This machine is intended to produce the most com- 
plete contraction of the pores of leather that can be 
attained, by means of two different movements combined 
in one, and by a pressure of from 18 to 20 thousand 
weight upon a surface of some fractions of an inch, this 
pressure being transmitted through the whole thickness 
of the skins without injuring or abrading their surfaces, 
and compressing those of different thickness with entire 
uniformity. 

The hides are placed upon the table e; the stamper Z, 
to which a round, oval, curved, or straight form can be 

* It will be observed that an occasioaal discrepancy between the 
lettering of the cuts and the references to them in the description 
occurs in this and a few other instances throughout the work. The 
errors are to be met with in the original French treatise much more 
frequently than in the present edition ; and those which have not been 
altered from the originals by the engraver, will be detected at once 
by any machinist. 



264 TANNING. 

given at pleasure, directed by the whole weight of the 
lever k; and the additional one of the lever p, passes 
over the leather and receives the oscillating motion given 
to the lever h, by the cranks h, Ti. It also receives an- 
other motion which makes it pass progressively across 
the breadth of the table, first in one direction and after- 
wards in the other, and which is caused by the screw 
which receives an alternate rotatory motion to the right 
and to the left, by means of the toothed shaft which 
catches in the pulleys to the right and to the left, being 
governed by the lever with the ball on top, which is 
drawn away from its centre of gravity by the projections 
d', d', of the rod h, and falls back upon the opposite side. 

The table being higher on one side than on the other, 
and the course of the lever passing the curved part 
where it is least elevated,, the stamper leaves the surface 
of the leather at short intervals, which are determined 
by each revolution of the wheels/,/, and the pressure 
being thus taken off, the leather can be moved by the 
workman and replaced in another position, so that the 
force can be directed successively upon the whole sur- 
face. 

The results of this operation are an immense economy 
of time, labor, and trouble, the greatest possible amount 
of compression and contraction of the substance of the 
leather, the securing of a perfectly uniform and smooth 
surface, and the accomplishment by one workman of 
what can only in common be effected by ten or twelve. 

Flotard and Belbufs Machine. — The following is« a de- 
scription of a machine invented in 1842, by Flotard and 
Delbut, taken from the Reports of Expired French Patents, 
vol. Ivii. p. 86 ; its object being to replace hand -beating 
by more active means, which will be free from the in- 



BEATING AND ROLLING BY MACHINERY. 



265 



conveniences attaching to other machines. To attain 
this end, the inventors have endeavored chiefly : — 

1st. To bring to perfection the construction of the 
mechanism moving the hammer, and 

2d. To make the anvil elastic, so that injury to the 
leather by the hardness and roughness of the blows may 
be prevented. 

3d. To use a table with a rolling surface, and with 
rollers attached to the feet. 

Figs. 49, 50, and 51. a. Cam, intended to lower the 
arm of the lever c, so as to elevate the hammer e. 

Fig. 49. 




5. Framework, or cast beam, supported on three co- 
lumns and sustaining the whole apparatus. 

c. Lever, having one extremity furnished with a 
wooden cushion, and the other rounded off to enable it 
to move freely in the mortice of the hammer. 

d. Cast arm, the end of which holds the helve of the 
hammer and maintains it in the vertical position. 



266 



TANNING. 



e. Hammer, having its lower surface covered with 
copper. 

f. Support, or anvil, composed of two principal parts: 
the one fastened to the ground, 1, is furnished with a 



Fig. 50. 



Fig. 51. 





grating, 2, which receives the fuel, and is attached by 
screws to masonrj-work ; the other part, 4, is that which 
receives the impulse of the hammer. It is movable, and 
mounted on twelve springs, 3 ; and its upper surface is, 
like the opposing one on the hammer, composed of cop- 
per. 

g. Flj-wheel, connected with the motive power by 
means of a band. 

Figs. 52 to 55. Hammer, of cast or wrought iron. If 
sufficiently small, it may be solid, but if large, should be 
hollow. 

a, a! . Wooden teeth, against which the cam h catches. 
These teeth are adapted to two mortises in the upper 
part of the hammer, and are retained in place by a 
wooden wedge. By means of the two teeth, the ham- 
mer can be elevated more or less, either by taking off the 
lower one a', or by enlarging or diminishing their size. 

h. Cam, acting upon the teeth a, to elevate the ham- 
mer. V . 

d. Cylinder, directing the hammer and keeping it ver- 
tical. This is furnished with two projections 3, which 



BEATING AND ROLLING BY MACHINERY. 



267 



support cushions for the shaft of the cam h. It rests 
upon a shoulder cV, upon the plate h'. The lips i, i, 

Fig. 52. 




against which the wooden teeth slide, prevent the ham- 
mer from turning. 

Two lateral openings, o, o, Fig. 53 (also seen in Fig. 
52), allow the cushions r, r (Fig. 54) to pass, which 
press the levers I, I, worked bj a screw, to the right at 
one end, and to the left at the other. Fig. 52 exhibits 
this arrangement. 

The shaft m, Fig. 54, serves as a prolongation of the 
screw n, Fig. 53, and carries a pulley v, Fig. 52, upon 
which passes a cord having a weight at one end, and a 



268 



TANNING. 



stirrup for the foot at the other. The cushions r, r, pro- 
duce a friction which slackens the fall of the hammer, 
and diminishes the force of the blow. 



Fiff. 53. 



■ ' t n. ' 



Sfvl 



'Fig. 54. 




d'. Circular plate, or cup, intended to receive the oil 
or grease dripping from the machinery, and which 
might otherwise fall upon and soil the leather. Fig. 51. 
Two vertical pieces, supporting horizontally a rabbit, or 
wooden spring, which is elevated or depressed by the 
screw attached to one end of it, so that the hammer a, in 
rising, touches it with more or less force, so as to aug- 
ment the power of the blow. A metal spring may be 
used in the place of a wooden one. 

/. Figs. 55 and 56. Table with rollers, p ; its feet rest 
on iron rails. 

T. Wheels, adapted to the feet of the table and running 
upon the rails. The skins to be beaten are placed on 
this table, and upon its middle the anvil, upon which 
the hammer descends, is supported. 

The anvil is chambered for the passage of a current 
of steam, for the jDurpose of warming the copper ftice, y ; 
and it rests upon springs, which are intended to render 
the shock of the hammer less severe, and to diminish 
the jarring. 



BEATING AND ROLLING BY MACHINERY. 269 

Fig. 55. 




Fiff. 56. 




As the system of vertical hammers has long been in 
common use, the invention of Flotard and Delbut con- 
sists, really, only in the use of 

1. The spring, for increasing the force of the blow. 

2. The check, for diminishing it. 

3. The cups, for receiving the oil drippings. 

4. The movable table, with rollers. 

5. The arrangement of springs, under the face of the 
anvil, and 



270 TANNING. 

6. In the passage of vapor. 

M. Berendorfs Machine for Pi-essing Bides. — The fol- 
lowing report upon and description of this machine is 
from the Bulletin of the Society for Encouragement of 
Arts, &c., of the year 1845, p. 68: — 

"The necessity of hammering by hand skins intended 
for sole-leather, formerly a very essential though fa- 
tiguing means of compressing them, has now been almost 
enj:irely prevented by methods which much more effect- 
ually answer the same purposes. Among these means 
. that of M. Berendorf, which substitutes for hammering 
a rapidly applied compression, somewhat analogous to it 
in operation, has been very successful. 

" The peculiarity of the mode employed by him in the 
use of the machine invented in 1844, consists not so 
much in this substitution of rapid compression for ham- 
mering, as in the peculiar arrangement of the support for 
the leather, which, by its elasticity, makes it possible to 
confine the amount of pressure to any desired limits. 
The support is an anvil, resting upon a spring composed 
of hard wood, the amount of resistance of which can 
be modified at pleasure by the workman, who, holding 
the hide by one hand, turns with the other^ screw which 
exactly regulates the pressure to which any particular 
part of the leather may be exposed. 

"The machine of Berendorf is powerful, and simple 
in all its parts. A beam acts upon a lever, the fixed 
point of which is attached to a cast-iron support, which 
forms the top of a frame large enough to receive a great 
number of hides, and having in its middle an opening 
through which the piston which produces the compres- 
sion by means of a lever about to be described, slides. 

"The compressing surfaces in contact with the hides, 
are made of brass, are smooth, convex, circular, and 



BEATING AND ROLLING BY MACHINERY. 



271 



have a diameter of from 3 yipth to Sj^-^th inches. The 
skins exposed to their action are beautifully smoothed 
and perfectly compressed by it. 

"The advantages of this process in improving the 
quality and appearance of leather, and its superior cheap- 
ness, have induced the council to bestow upon M. Beren- 
dorf a silver medal, and to insert in their Bulletin this 
report, accompanied by a description and plate." 

This machine is composed, 1st, of a movable vertical 
hammer, which exerts pressure upon the hides. 2d, Of 
a fixed anvil upon which they are placed. 3d. Of a. 
lever which gives the impulse to the hammer. 

Fig. 57 exhibits a front view of this machine. 



Fig. 5T. 




Fig. 58. A p^an. 

Fig. 59. Vertical and cross section, made upon the 
line A, B, in the first figure. 



272 



TANNING. 



Fis. 58. 




The same letters apply to all the figures. 

1. The wrought-iron hammer, A, is furnished, at its 



Fig. 59. 




Fig. 60. 



Fig. 61. 




Fig. 62. 



Fig. 63. 



^ hi ^ 






inferior extremity with a face of bronze, and its cylin- 
drical shank or helve passes through a vertical socket in 



BEATING AND ROLLING BY MACHINERY. 273 

the large and strong cast-iron beam B. This latter, 
which is represented in cross section by Fig. 60 (upon 
the line CD, Fig. 57), is strengthened by mouldings, 
and rests, by its extremities, upon two cast upright 
columns O G, with which it is firmly connected. The 
space between those uprights, amounting to but 78 
inches, only admits half hides, although M. Berendorf 
has also adopted another arrangement represented in 
Fig. 61, which admits of acting upon whole ones. About 
the middle of the upper part of the beam B, and near 
the socket, is a projection D, which supports the end of 
the lever that transmits its action to the hammer. 

2. The anvil which receives the leather to be com- 
pressed, is composed of an iron cylinder E, having a 
brass face a', like that of the hammer, and between these 
two the leather is pressed when the latter descends. 

The cylinder passes freely through the socket of the 
large cross-piece F, and rests upon an elastic support, 
which allows it to descend a little under heavy pressure, 
and to rise again rapidly. This support consists of a 
thick wooden plank (7, 20 inches square, fixed at its ends 
to the lateral projections c, which descend to the foot of 
the columns with which they are connected. This piece 
of wood-work is so large that it often has to be made of 
two pieces bound together by screws with nuts d. The 
cylinder does not rest directly upon this wood, but upon 
a steeled gudgeon, or pin, Fig. 62,/. The gudgeon or 
pin is threaded for part of its length, and traverses a 
copper nut g, sunk in a cast-iron rim A, which is let into 
the centre of the wooden support. By turning this pin 
to the right or left, the cylinder and the anvil face a' are 
made to rise or fall along with it. To efiect this move- 
ment, the workman grasps a little fly H, the axle of 
which has an endless screw which works a toothed-wheeL 
18 



274 TANNING. 

/, mounted upon the gudgeon. The fly is turned more 
or less, as the thicker or thinner parts of the leather are 
being exposed to pressure. 

The leather placed between the anvil and hammer is 
thus pressed to any desired extent, and, the wood below 
being elastic, bends or gives to some extent, and again 
rebounds to its original position. 

The cast cross-piece F which guides the anvil, rests at 
its two ends upon the projections i i of the columns C C, 
and upon each side of it is placed a table J, upon which 
the workman moves the hide in every direction, so that 
it may be touched at all points successively. 

3. The lever which acts on the hammer. The head 
of the hammer A incloses a steel block, upon which a 
prop j pivots, which is of ovoid form and well-tempered 
steel (Fig. 59) ; and upon this prop the large lever K, 
moving upon the axis Tc, Fig. 63, is supported. When 
it descends, it rests upon the prop j, which oscillates a 
little upon its centre, and forces down the hammer in a 
vertical direction, and, in order that it may rise again 
with it, they are connected together by two iron bars, 
terminated by arms, which are attached on one side by 
the bolt OT, which passes through the lever, and on the 
other by a similar bolt n, which goes through the head 
of the hammer (Fig. 59). The play given to these arms 
is regulated by small compressing screws above them. 

The steel axis h, upon which the lever moves, rests 
upon the upper part of the projection D. A steel ring, 
traversed by the axis h, is adjusted upon the centre of 
the lever-head, and can be easily replaced when worn 
out. In order to retain this axle in place, it is covered 
on each side of the lever by two strong stays, the 
branches of which extend to the top of the beam, as well 



BEATING AND ROLLING BY MACHINERY. 275 

as to the projection D, and are kept in place by strong 
nuts. 

M. Berendorf moves his machinery by a small oscillat- 
ing cylinder engine, the power being transmitted to the 
lever K by the two beams L L, joined together by the 
double crank M. The vapor enters the conical box Q, 
from the boiler through the pipe s, raises the piston, and 
escapes by the pipe t. The fly R turns the small crank 
z, and works the feeding pump S, which is plunged in 
the reservoir T. The water is returned into the boiler 
by the tube a", when the cock h' is open, and a ball-cock 
keeps up the communication between a reservoir above 
and the one below. 

This machine works ordinarily at the rate of 140 revo- 
lutions in the minute, during which time more than a 
square yard of surface is compressed by it. In M. Beren- 
dorf's establishment, where a number of machines are 
constantly working, from 70 to 80 half-skins are pressed 
by each apparatus in twelve hours. 

Berenger and Co. have three mill-hammers at work, 
at the rate of 100 blows a minute, each one turning out 
from 35 to 40 whole skins in a day. 

M. Berendorf has taken out a patent of fifteen years' 
duration, dating the 7th of October, 1842, and, still later, 
two additional ones of improvements upon this interest- 
ing machine, which is now completely established in 
favor. 

Cox^s Machine. — A more modern method of rendering 
leather smooth and compact, is by passing it between 
rollers. This mechanical arrangement, being free from 
tremulous motions, and easily adjusted to any desired 
rapidity of action, produces a uniform and powerful 
compression throughout the side of leather, without any 
liability of damaging it, as is the case in machine heating. 



276 



TANNING. 



Cox has invented a rolling mill in which the roller is 
fixed at the end of a lever, which, being suspended, 
oscillates like the balance of a pendulum. 

This roller, made of copper or brass, 5 inches in 
diameter and 9 inches in length, is suspended by its 
axes in the chaped end of an iron lever 6 inches in 
diameter and 11 feet 10 inches long. The upper end of 
this lever, also terminating in a chape, is movable upon 
pivots attached to a beam or block 15 feet long and 2 
feet wide. This beam is free at its anterior extremity, 
and is so jointed at the other as to enable it to move 
upwards and downwards, and it rests on each side upon 
two supports placed below it. The weight is in a box 
resting upon the body of the lever, which is moved by 
the aid of a crank attached to it at a distance of rather 
less than two feet above the roller. The lever should 
move through a space of 3 feet 8 inches, but this can be 



Fig. 64. 



Fig. 65. 




C 



S ^ Fi 



3 




increased or diminished. The copper or brass support 
is hollowed out, so that the roller can pass along its 
whole extent, and reach all parts of the leather. As 



BEATING AND ROLLING BY MACHINERY. 277 

soon as the hide is placed upon this support, the block 
or beam is made to rise, and the whole weight bears 
directly upon the leather. At the end of its course, 
where the support is flat, the roller is raised up by the 
beam, the weight is borne down again upon the leather 
when it reaches the middle, and is again elevated by the 
supports placed under the beam. 

Fig. 64 is a front view, and Fig. 65 a side view, of this 
machine. F, beam, movable at its hind end by a hinge 
(7 fixed in the wall (Fig. 66), and maintained in a hori- 
zontal position at the other end by the sup- 
ports BB. P, lever joined to the beam F by Fig- 66. 
the pivots S S, and terminated by a fork M [K_ 
which holds the roller R, running over the 
curve A. This curve has, at either end, a 
plane surface E, where the roller leaves it and is raised 
up by the pivots S. D is the horizontal shaft connected 
with a crank which moves the lever P, and (7 is a box 
containing a weight heavy enough to cause the necessary 
pressure at the moment when the roller reaches the 
plane end of the support. 

Wiltaes Rolling Tahle. — This machine, somewhat simi- 
lar in construction to the preceding, is shown by the 
accompanying drawing, Fig. 67, made to a scale of the 
eighth of an inch to a foot. The machine consists of a 
spring pole, a lever h, to which the head of the vibrator 
d is attached, and which is rendered compound by a 
connection with a second lever c. This combination 
acts through the vibrator d upon the roller g, and is 
propelled by the foot working the treadle e e. The bed 
h is of lignum-vitaa wood, and the table i, upon which 
the leather is spread while being gradually drawn unfler 
the roller, is 8 feet wide and 16 long. The bed is the 
part upon which the leather is rolled, and is firmly sup- 



278 



TANNING. 
Fig. &1. 




ported by a heavy log J, which, in its turn, rests securely 
upon the supports o o o o and the sill n of the building. 

Jig. 68. 




E 



E 



B 



Lajf 



^7 



•^Cf-li G\^^ 



BEATING AND ROLLING BY MACHINERY. 279 

The connection/ with the balance-wheel h forms a crank 
by which a vibrating motion is communicated to d. The 
pulley m on the same shaft is the driving medium, and 
the roller should move at the rate of 130 revolutions a 
minute. 

Fig. 68 is a view of the rollers A A, one of which is 
represented as it is retained in working position by the 
straps B B, and the other detached. A side view of 
the strap is also given in a separate figure B. The 
wrench C is used for turning the nuts E. The lips F F 
are oil-holes for lubricating the journals of the roller. 

The roller is made of a composition of copper and tin, 
with a steel shaft penetrating through it. 

These mills and appliances are made in a creditable 
style of art by Wiltse and Co., Catskill, New York. 

Seguiris Machine to Flesh and Gloss Leather. 

This machine is composed of two metallic rollers six 
feet long; one carries a sharp blade spiral in form, and 
is destined to flesh the skin enveloped on another roller 
21 feet in diameter, while the first is but six inches. 
On the circumference of the lower roller and parallel 
to its axis a groove is made in which the end of the 
leather maintained by hooks, is engaged; the sharp blade 
is thus disposed to form from the centre of the roller a 
spiral which makes a full turn to the two ends. The 
pivots of the rollers turn those of the lower roller in fixed 
steps, and those of the upper roller in true levels by which 
they raise or lower this last roller to make it stand on 
the large roller. The movement of these rollers turning 
in opposite directions is combined so, that when the 
upper roller makes a full revolution, the lower one ad- 
vances only yL of its circumference. The pressure of 
the upper roller on the leather can be regulated by load- 



280 TANNING. 

ing the levels with weights, more or less heavy, the 
leather, being engaged by the end in the groove of the 
lower roller, rolls around this roller as soon as it turns. 

At that moment they put the sharp blade of the lower 
roller in operation, so that the skin is fleshed from the 
centre to the ends on all its length. i 



CHAPTER XLIII. 

TISSUE AND QUALITY OF LEATHERS— THEIE DEFECTS 
AND THE WAY OF ASCERTAINING THEM. 

We have made known the composition and structure 
of the skin; it is then evident that well-tanned leather 
ought to form a homogeneous body from which it is im- 
possible to extract fibrin and gelatine. These principles 
are in a state of perfect combination, and while the 
fibrous tissue is not destroyed, it is, however, reduced to 
such a state that it is not fibrin. According to what we 
have indicated before, it is evident that if barks of good 
quali,ty have been used, if the operation has been well 
conducted, the leather must be of good quality; but if 
one or several of these operations have not been well exe- 
cuted, and if the barks are poor in tanning principles, 
the leather presents imperfections which diminish its 
quality. It is ordinarily by cutting, that the quality of 
leather is ascertained ; that well manufactured presenting 
a bright cut and a hard body. It is everywhere, except 
on the hair side, of an equal color, and the inside has the 
appearance of an open nutmeg. The tail, the back, and 
the throat being the thickest and most essential parts, 
are those which are cut in order to ascertain the quality 
of the leather. 



TISSUE AND QUALITY OF LEATHERS. 281 

You can judge a leather is badly manufactured or im- 
paired when its edge is yellowish or blackish, when you 
perceive in the centre a black or whitish line, and at last 
when its tissue is loose and spongy. 

Too long a stay in the vats, the vat being badly com- 
posed or managed, a want of dampness in a vat which 
loses water, and other different circumstances, may 
deteriorate the leather. Then you perceive that it is 
spongy, too open, wants weight, has not the proper color 
nor the requisite hardness to be good in use; but the evil 
is without remedy, and the quality cannot be restored. 
Generally the outside color of leather depends on the 
manner in which it has been swelled and tanned. The 
leather swelled with lime is nearly black on the hair 
side, and red on the flesh side, the inside is light red; 
the color of leather raised with barley is slatish on the 
hair side, and whitish on the flesh side and the edge. 
That with garouille bark is of a blackish-brown, and has 
a strong and disagreeable odor that it always keeps, 
while leather tanned with birch has an agreeable odor. 

It is impossible to tan perfectly the thin, hollow, and 
dry skins, those which are difficult to swell, or those 
which do not swell in a satisfactory manner. 

It is also difficult to prepare well, skins which are full 
of cuts, and those from Ireland, and Brazil. Skins put 
into muddy waters are often pricked; there are some 
others so difficult to depilate, that there remain on the 
side foreign substances, thus explaining the reason why 
in working on the beam they are cut, becaus6 those 
parts which are hard resist the knife. 

When the skins have remained too long in the lime, 
sometimes they are burned in such a way, that by taking 
them with the nippers they are torn, and it is nearly 
impossible to flesh them. It is a fact beyond question 



282 TANNING. ^ 

that a fresh, clear, and pure water is the only one proper 
for the preparation of leather. 

Leather is called horny when some parts of it are 
dried and hard as horn, because not having been soft- 
ened the tan has not penetrated them. To obviate 
this defect you must be careful not to leave them in 
the open air. 

Some leathers contain a multitude of small holes; 
these holes deteriorate the leather to such an extent 
that it lets in water. A good plan to test the quality 
of a leather is to put into water a piece previously 
weighed, and leave it in for a few days. If, when with- 
drawn, this leather has acquired a considerable weight 
in proportion to its volume, it is a sure sign that it is 
spongy and consequently badly tanned. If, on the con- 
trary, its weight is nearly the same as before, the leather 
is of good quality; consequently the more dampness a 
leather absorbs, the more spongy it is. 

Leather kept more than two years does not improve 
in quality. It dries and diminishes in weight, which is a 
loss to the manufacturer, who should keep it in a damp 
store. 

Action of Frost on Leather. — Many inquiries have 
been made for the purpose of ascertaining whether the 
freezing of leather will add to its weight. We answer 
no, quite the contrary. The particles of water freeze 
within the pores of the leather and become expanded, and 
to that extent that the sides appear Hoaied. But when 
the icy particles melt away, the side is left in a spongy, 
softened state, which very much injures the fibre of the 
leather, and to some extent takes from the weight of 
the side. We are not unaware that some tanners infer, 
because they get a larger gain in weight in winter than 
in summer, that this gain is in some way the result of 



TISSUE AND QUALITY OF LEATHERS. 283 

frost, but this fact is attributable to other agencies, which 
we will not consider at this time. 

The influence of frost upon color is very marked, and 
is attributed to a chemical change, and it is a fact that 
leather frozen dry will be many shades lighter in color 
than if dried by any artificial heat. It is also true that 
leather thus dried is much softer, but then this is clearly 
attributable to the heaving of the fibre by the frost. It 
is a sad mistake to suppose that frost adds either to the 
weight or quality of leather. The only good it can 
accomplish is on short, tanned or crusty hard leather, it 
directly tends to overcome those difficulties; but upper 
leather and calf frozen dry will always cut a flesh more 
open and coarse than when dried by the natural air 
without freezing. We do not allude to this subject just 
now so much to correct errors on this point, as to 
suggest that the whole subject of drying leather should 
receive more attention. Suppose it can be demonstrated 
that sole-leather can be dried in forty-eight hours 
without injury either to the weight or color; how val- 
uable would such an improvement be. Under such 
circumstances no tanner would require more than 1000 
to 1500 sides exposed at any one time, besides saving 
the interest for at least one month on his whole stock. 

It is believed that steam when properly applied can 
accomplish this result, and it has been done as we shall 
see hereafter. 



284 TANNING. 



CHAPTER XLIV. 

BELT LEATHER. 

The name of helt, or crop leather, is applied to leather 
made from the skins of cows or small oxen, provided 
they possess sufficient thickness, as their tissue is more 
compact than that of ox-hides, at least, if the cows have 
not already calved. The skins of young oxen are defi- 
cient in thickness and firmness, and are only used for 
conversion into belt leather. 

This kind requires a much more thorough currying 
than thick hides, which are almost fit for use when 
taken from the tanning. It is employed principally by 
shoemakers for second soles and uppers for women's 
shoes and men's light shoes and pumps. Young ox-hides 
are regarded by shoemakers as inferior to cow-hides ; and 
they use the latter for upper and thin soles. The tan- 
ning of these hides is conducted in a somewhat different 
way from that of thick hides. 

At first, they are placed in the lime pits ; and, when 
ready for depilation, which is generally in eight days 
during summer, and ten or twelve in winter, are repeat- 
edly fleshed and scraped, care being taken to rinse them 
each time in clean and running water, if possible, so as 
to remove all the lime. Those intended for uppers re- 
quire at least four or five rinsings, while two will suffice 
for those which are to be used as soles. They are then 
deposited in wooden vats, 4i feet in height and 6i feet 
wide, which are nearly two-thirds filled with weak in- 
fusion of oak bark, and are handled daily. 

If the hides are worked in the sgi^pie vat, the strength 



BELT LEATHER. 285 

of the infusion must be restored as rapidly as exhausted 
by fresh additions of bark. 

When transferred to other vats the liquor must be 
made successively and successively stronger. Usually, 
tanners prefer this method; but, sometimes skins are 
treated in hot infusions, prepared in vats similar to those 
just described, by adding hot water to bark in the pro- 
portion of five baskets for every twenty-four cow-skins. 
After being placed in the vats, the skins are repeatedly 
handled or moved about by the workmen. This work- 
ing is frequently repeated, the skins being taken out 
daily to drain ; and a little fresh bark being added to 
the vats in the interval. This manipulation is continued 
from four to six weeks. The following figure represents 
the operation. 

Fig. 69. 




Whichever of these methods is adopted, the hides are 
next subjected to a mixture of ground bark and strong 
liquor in other vats. For this purpose the bottom of 
the vat is covered with a layer of fresh tan, carefully 
moistened, upon which a skin is spread out to its full 
extent; this is covered with another layer of tan, and 
the hides and bark are alternately packed in till the vat 
is full. The top hide must have a " hat" of bark, and the 
contents of the vat be then drenched with the solution. 



286 TANNING. 

The workman should be careful to place the skins in 
every direction around the pit, the end of the contiguous 
ones forming slight angles with each other, and to deposit 
tan in all the creases and doubling made by the bending 
of the edges. This process usually requires six weeks. 
Five baskets of tan are used for a dozen ordinary cow- 
skins, and about six for six dozen young ox-hides. The 
skins, having undergone this preparation, are then further 
exposed to two treatments in the vats in precisely the 
same manner. After remaining in the first pit for three 
months, they are taken out, and, before being transferred 
to the second one, are beaten or trod out for the purpose 
of rendering them more supple. This process having 
been completed, they are placed in the second and last 
pit. Some tanners are satisfied with five weeks' expo- 
sure in this last pit ; some others extend the time to 
three months. This latter period is not too long for 
leather of good quality. After withdrawing, the leather 
is dried in the usual manner, being careful not to expose 
it to the sun, a strong wind, or a cool or damp atmosphere, 
in which it might mould ; then it is transferred to the 
currier, who prepares it according to the kind and quality 
of the leather required. 

Cow-skins differ much in quality, those of the younger 
animals being much superior to those of cows which have 
frequently calved; the latter having become weak and 
thin by the distension to which they have been subjected. 
Young ox-skins also, long regarded as inferior to the 
latter kind of cow-skins, are equally serviceable; and 
the shoemakers now use them indifferently. 

The above process is employed in the best establish- 
ments of Paris ; but, in the provinces, some tanners vary 
it more or less. 

In Brittany this leather is made by the process of 



BELT LEATHER. 287 

tanning in sacks. After having been exposed in the 
lime pits for two months, and placed for eight days in 
hot ooze and water, they are then filled with the decoc- 
tion, and left for a week or more, being careful to change 
their position five or six times a day. Then they are 
unripped, placed between layers of bark, and allowed to 
remain untouched during eight days before being finally 
taken out and dried. 

In Limousin they are limed for four days, then placed 
in the tan pits, in which they are allowed to remain for 
three months. 

In Dauphine they are limed for fifteen days, then 
exposed for four weeks to two different treatments with 
barks, and transferred to the vats, where they remain 
for Ih month. 

At Metz and Yerdun, after having lain for eight days 
in old lime pits, and as much longer in fresh ones, they 
are exposed to the action of ooze for one month, and 
afterwards to two stratifications with tan for five months 
longer. 

At Bourges and in different places in Berry they are 
allowed to remain three months in the lime pits and 
six months in the tan vats. 

At St. Germain, cow and calf-skins are passed through 
three old lime pits and one fresh one, and then undergo 
five cleanings and rinsings. They are then beamed and 
relieved with the knife of all superfluities, and worked 
upon the hair side with a whetstone, and when thus 
well softened and clean, are again thrown into the water. 
After being worked for the third time upon the horse 
with the round knife on both sides, so as to expel the 
last portion of lime, they are again rinsed ; and a fourth 
and fifth time treated in the same way. The final rinse 



288 TANNING. 

water should come from them perfectly clear, and leave 
them in a proper state for the ooze bath. 

How to Manufacture Gow-leailier into Uppers of a su- 
perior quality, — In order to be good, upper leather 
should have the following properties : — 

1st, the pores should be very close, constituting its 
solidity. 2d, the leather should remain pliant and not 
break easily in use. 3d, the leather should be water- 
proof, so that the feet may be kept dry in the dampest 
weather. 

The following instructions should be observed in manu- 
facturing cow leather uppers possessing the above named 
properties. In choosing the hides such skins only should 
be selected as are of light weight, and whose exterior 
promises leather of a superior quality. In the selection, 
attention should be given above all things to the hair; 
if it is fine and glossy, it is an evidence that the animal 
was well fed. The next point is the horns ; if they are 
short and sharp pointed, then the animal was young. 
With regard to the flesh side, it should be as even as 
glass and devoid of the bites of cattle worms. If other- 
wise the skins are free and thin, they may be considered 
in a suitable condition to be transformed into fine upper 
leather. 

In places where this sort of cow-skins accumulate, it is 
advisable to work them while they are still fresh. It is 
true that it is necessary to pare them before putting 
them in water, still the drying operation is gained by 
this, and the leather made from them is as good and 
even more heavy than that produced from milled hides. 

But as the tanner does not receive many fresh hides, 
he is obliged either to buy dry hides or to have them 
dried himself. In the drying operation great care must 
be taken, especially in summer and autumn, that the 



BELT LEATHER. 289 

hides while suspended on poles do not rot and lose their 
hair, which unfortunately happens very often. 

In order to avoid rotten spots, Mr. V. Mathesias pro- 
ceeds as follows : When the hide is laid on the table, 
first remove all the fat, then stretch it well out, and 
sprinkle it with about one pound of salt, and as soon as 
it has been rubbed in hang the hide up. It is not then 
necessary to stretch it so carefully. Thus, this advan- 
tage is gained, that the hides being dry they are seldom 
attacked by moths or worms. Another advantage is, that 
they are much easier to refreshen than hides which are 
not salted. In my opinion, there is no need to give heed 
to the fresh, especially when one is able to use block 
salt. 

It is not advisable to put more than from twenty to 
twenty-four hides into the water at a time, even where 
upper leather tanning is carried on on a large scale; 
still, in the spring the number may be doubled, for the 
reason that the vats can be filled at several stages. 

The first day, the skins to be refreshened should be 
hung in running water ; and in places where this is not 
practicable stretch them out, and pour water upon them 
time and time again. 

After the hides have become softened by this ope- 
ration, they should be placed in the vat, and, if pos- 
sible, add spring water until the hides are entirely 
submerged. The next day raise them, and put them 
back. This is necessary to make the tanning uniform. 
The fourth day raise them again. This should be done 
often if the weather be warm, and also if the water in 
which the hides are soaked be hard; then they may be 
stretched on the apparatus for that purpose ; but, before 
doing this, it should be ascertained that they are soft to 
the touch. Then they are to be cleaned, in order that 
19 



290 TANNING. 

they may be stretched lengthways on the table which 
has been previously covered with one hide. 

When hides have been salted before drying, or when 
they have not been salted at all, provided that they 
have not been dried too much, the stretching operation 
is easy ; but there are cases, especially if the skins have 
been dried in the sun, when this operation requires much 
force, especially when the skins known as hips are con- 
cerned. After having properly stretched the skins, they 
should be put back into the same water from which they 
have been taken. The next day raise them, and exa- 
mine whether they have become well-soaked. If you 
find any that do not appear to give satisfaction in this 
respect, put them back ; but if there are any that are still 
very hard, these should be stretched again. It is abso- 
lutely necessary that .the hides should be completely re- 
freshened before being placed in the lime pit. If they 
are placed in it in a hard state they will remain hard, 
even after they have become converted into leather. 
Therefore, we may look upon the refreshening as the first 
basis of the tanning of pliant leather. 

East India kips, which for many years past have been 
tanned into upper leather, require a special mode of 
treatment for the refreshening. In India, they are first 
stretched, and dried by the heat of the burning sun ; 
then, in order to protect them against worms, while they 
remain in store and during their long voyage, they are 
sprinkled with lime or nitre dissolved in water, or with 
arsenic. They are, therefore, often very difficult to soak ; 
some of them cannot even possibly be well refreshened, 
as they are half burned. This species of hard hide is 
tanned for the purpose of making inner soles. At least, 
this is the best use to which they can be put. 



TANNING OF CALF-SKINS. 291 



CHAPTER XLV. 

TANNING OF CALF-SKINS. 

The tanning of calf-skins is conducted much in the 
same way as small cow-hides. After being pressed to 
expel oleaginous matters, they are passed three times 
through old, and once through fresh lime vats ; but, being 
too weak to bear the full strength of the lime, this should 
be done after the passage of cow-skins through the vats 
has somewhat diminished its activity. If they are dried 
when brought up into the tannery, they must be first 
trodden out and soaked. Then they are scraped, care- 
fully fleshed and rinsed, after which they are ready for 
a part of the process differing from that used for cow- 
skins. 

Place from fifteen to eighteen skins in a tub, beat them 
for eight or ten minutes. This operation softens the 
fibre, and is repeated after each rinsing, but it is omitted 
in establishments where the skins are rinsed as often as 
six times. The beaters are wedge-shaped, from 8 J to 10 
inches in diameter. 

The skins, being entirely free from hair and lime, are 
placed in the hot ooze and water, and treated like cow- 
skins, excepting that they require more frequent and care- 
ful handling. Be careful to put fresh tan each time into 
the vats. Submit them to the action of stronger ooze, 
and tan in the same way as other skins for a month, 
when they are afterwards transferred to the pits. In 
these they are folded lengthwise and unequally, and 
thus spread over with tan, being careful to cover the 
heads and tails with rather more tan than the other 



92 TANNING. 

parts. The tan used should be of the first quality. They 
are exposed in the first pit for three months. They are 
then taken out, freed from all particles of tan which ad- 
here to them, and placed in the second pit with tan which 
is reduced to the finest state of division. They are folded 
double, and unevenly as before, but in such a manner 
that the part before covered shall now be exposed. Fill 
up the pits as usual; moisten the whole with warm 
water, and leave three months, then the skins are ready 
to be curried. 

Some tanners, instead of using cold water to moisten 
their pits with, employ a warm infusion of bark, which 
is an improvement upon the old process. 

As it is important to have the skins soft and ready to 
absorb the tanning liquor, some tanners remove all 
traces of opposing substances, such as grease, lime, etc., 
with the help of an alkaline lye, which consists of water 
impregnated with pigeon's or hen's dung, and is techni- 
cally called a hate. Ten or twelve gallons are sufficient 
for one hundred skins ; and during the time they remain 
in the last liquor — from eight to ten days — they are fre- 
quently handled and scraped. After the action of the 
bate, the skins assume the form of jpelts, in which state 
they are placed in the ooze vats. The bate acts by means 
of its hydrochlorate of ammonia. The lime in the skins 
decomposes it, takes its acid, and becomes hydrochlorate 
of lime, which is soluble, and carried away by the wash- 
ing waters, while the ammonia disengages in a gaseous 
state. If the dmig is fresh, the organic matter it con- 
tains is liable to putrefy, which involves a partial decom- 
position of the gelatinous tissue and a loss, and at the 
same time imparts a very disagreeable odor to the lea- 
ther. 



TANNING OF CALF- SKINS. 293 



CHAPTER XLVI. 

TANNING OF CALF-SKINS FOE THE PREPARATION OF 
WAXED CALF-SKINS. BY MR. RENE.' 



Before entering into the details of the manufacture 
of waxed calf-skins, which within the last thirty years 
has attained to so great an importance, we wish to say 
a few words on the origin of this speciality, and of the 
time when this kind of work began to be seriously de- 
veloped in France. 

About fifty years since, the fabrication of waxed calf- 
skins was scarcely known in France ; only black-grained, 
stamped, and white calf-skins were produced. The first 
two articles were already well made ; they alone with 
cow-hides in oil being used for men's and women's shoes. 
The white skins were exported to Spain, Portugal, Italy, 
Constantinople, Smyrna, Alexandria, Malta, and Sicily. 

Let us describe in a few words how those white calf- 
skins were prepared. "We shall not, at present, speak 
of the method of tanning. We wish only to make 
known the processes to which they were subjected after 
tanning, in order to prepare them to be delivered for 
exportation. 

On being taken from the pit they were piled lightly 
for drying, then scraped, either over a horse with a tan- 
ner's knife, or on a table with a stretching iron, but this 
was done very lightly ; then they were placed in oil of 
a rather thin consistence mixed with fish oil. On the 

* From " La Halle aux Cairs." Paris. 



294 ' TANNING. 

fleshy side they generally used fine degras, such as is 
used by chamois dressers; they were then hung up 
to dry. The calf-skins being dried after laying some 
days in a pile, were folded muff-like, and pressed on the 
bickern, beaten well on the bench with a cork club, then 
turned again and scraped against the grain with the same, 
and finally grained with a cork board from the four false 
quarters, and then they were ready for exportation. 
These calf-skins presented a clumsy resemblance to the 
rough Milan skins. 

About 1808 four Irish curriers established themselves 
in France. They were expert workmen, and they brought 
with them a new branch for us in the leather business, 
and the speciality at length placed French currying in 
the first rank, for it may now be said to be without a 
rival in this particular kind of manufacture. These 
Irish workmen formed apprentices; and, after Paris, 
Pont-Audemer had the first instructed workmen. It was 
also through those Irishmen that we learned to curry 
horse-hides. 

At that time France was in the middle of a long war 
with England, the ports were blockaded, and the demand 
was only for home consumption. Consequently few 
waxed calf-skins were manufactured, except for large 
cities where they were used for elegant shoes. Waxed 
calf-skin was then employed much as varnished calf- 
skin has been within the last ten years, during which the 
fashion of wearing patent leather shoes has been com- 
mon in the cities,. while in smaller towns, cow-hide in 
oil and grained calf-skins . formed the principal staple of 
consumption. Horse-hide, when known, became a 
rage ; every currier produced smooth horse-leather, until 
it came to be the patent leather of the time. In 1814, 



TANNING OF CALF-SKINS. 295 

the style of boot introduced by Russians, of white calf- 
skin, diminished the call for horse-hide. We may say at 
once that the English were then far from having reached 
the perfection attained in our day in the preparation of 
upper leather. The waxed calf-skin alone was finished 
of about the same quality as now, and even better. 

The fabrication of boot legs, then, from 1814, rapidly 
improved in France; but waxed calf-skins, properly so- 
called, were still in the back-ground, if not as a manu- 
facture, at least as an important article of sale. 

II. 

Classification of Untanned Calf-skins. 

Untanned calf-skins, the manufacture of which we are 
about to describe, may be divided into four classes, viz : — 

1st. Calfskins fresh from the butcher's. 

2d. Salted calf-skins. 

3d. Dry French and European calf-skins. 

4th. Dry calf-skins from the East and West Indies. 

Washings. — On receiving the skins fresh from the 
butcher, they are placed in water for washing; not in 
running water, because it is too cold in winter and too 
warm in summer. In the absence of spring water, we 
use that from the pits. In the centre of the work-house 
or in the corner is a large reservoir rising at least 6 feet 
above the ground; there the water is collected and dis- 
tributed about the establishment. Soft water is preferred 
as less charged with calcareous matter than hard water, 
which often holds in solution earthy salts. 

I use a pit built of wood. As soon as the skins come 
from the butcher I plunge them into this pit, unfolding 
them one by one, and being careful to scatter them about 
the vessel with a stick. 



296 TANNING. 

One hundred calf-skins weighing from 1000 to 1200 
lbs. are enough for any allowance of water; fewer may 
be taken, but if more are put in they will not be well 
cleaned. In summer I let the skins soak six hours, and 
twelve hours in winter, according as the temperature 
rises or falls, after which I take them out of the water. 
Then I empty the pits and refill them with clear water, and 
replace the skins as at first. In about six hours in sum- 
mer and twelve in winter, I examine them, the flesh is 
white, the little veins have lost their blood. I draw 
them and give them, while on the horse, light blows 
with the iron on the flesh side. 

Liming. — The calf-skins being now sufficiently cleansed 
and drained, I set about placing them in lime-pits. The 
lime-pits are three in number, each 52 cubic feet. In 
one is the dead liquor or the oldest, in another the gray 
or the second in strength, and in the third, the fresh 
strong lime, which is the most active. By means of a 
large hoe, I agitate the contents of the dead vat as much 
as possible, and when sufficiently stirred I cast in my 
calf-skins, one by one, unfolding them well and sinking 
them in the liquid as fast as I plunge them in. This 
done, they are left undisturbed for twenty-four hours; at 
the end of which they are drawn off" with iron tongs. 
When they are out I stir up the lime-water anew, and 
immerse the skins in it for another twenty-four hours. 

This is done with fresh skins from the butcher; but 
if they are slightly tainted, I pass them in the gray solu- 
tion, and even into the strongest one, in order to help 
their preservation. If they begin to decompose when 
received from the butcher, I rinse them carefully, beat 
them on the flesh side, and cast them immediately into 
the strongest lime-pit. I take up the skins which have 
been immersed in the dead solution for the second twenty- 



TANNING OF CALF-SKINS. 297 

four hours; I pass them into the second solution, where 
they are worked as in the first, and left forty-eight 
hours, being careful to raise and beat them after each 
twenty-four hours. 

At the end of these four days of liming, it frequently 
happens in summer that a third, a half, sometimes even 
all the skins are stripped of hair. In such a case they 
are immediately taken out; otherwise, I pass them 
in the quick vat, where I leave them until the process 
is completed. But, generally, in twenty-four or forty- 
eight hours the end is attained. I allow the skins to 
drain, and put them into a tub with just water enough to 
cover without floating them; there they are submitted 
to the first disgorging process. They can, if necessary, 
remain in this water ten or twelve days. 

I prefer this method to piling, for in the water calf- 
skin parts with the lime, and the action of the latter is 
weakened. While in the pile it continues to work, and 
if my men in piling do not exercise care, they catch what 
curriers call the plis de pelain, a disease almost impossible 
to banish from currying establishments. But the sum 
of all this is, as soon as the skins are unhaired, they are 
to be taken out and rinsed in a vat or washed imme- 
diately in the river ; in this first process, then, it is ad- 
visable to be as quick as possible, for I repeat that liming 
calf-skins is not tanning them. We have heretofore 
omitted to indicate the manner in which the three pits, 
called the strong, gray, and slake pits, are prepared. 

Into my pit, the capacity of which is about fifty-two 
cubic feet, I turn about one hundred and ninety-eight 
gallons of water, and add thirty-nine gallons of fat lime; 
this is for the strong pit. In the gray pit I mingle the 
same quantity of water and twenty-five gallons of lime; 



298 TANNING. 

in the dead put for the same quantity of water from 
twelve to fifteen gallons of lime. 

I keep alive my pits while they are in use with slacked 
lime, in such a way as to preserve the relative strength. 
I renew my live pit ; for about every six weeks, or at most 
two months, it degenerates to the strength of the gray 
pit, and the gray to that of the slack. In order to re- 
make the live pit, I first empty and cleanse the dead 
pit, for I believe this step to be necessary to the health 
of the workmen and salubrity of the establishment. 

Salted Skins. — These hides are cleansed from the salt 
and blood in twenty-four hours; then they are taken 
from the water and struck with the iron upon the fresh 
side, then replaced in clean water for twelve hours, after 
which they are removed and allowed to drain off"; finally, 
they are put into the slake pit, following the same course 
as with fresh skins. 

Dried Calfskins. — For calf-skins, dried in hair from 
France and other parts of Europe, I pursue the following 
method : — 

The skins are soaked forty-eight hours ; at the expira- 
tion of that time, I raise and lower them in the same 
water, and let them remain another forty-eight hours. I 
then raise them again and straighten them very carefully 
with the stretching iron, especially on the parts not 
affected by the soaking. 

The edges and the necks should be worked with 
nainute attention; every fold should be opened, and the 
stiff" parts of the neck should be unrolled with the hand. 
This work finished, and I replace them in water for 
twelve hours, then withdraw them, let them drain, and 
send them to the dead pit, which I have taken care to 
weaken, because, for calf-skins dried in the air, the pits 



TANNING OF CALF-SKINS. 299 

ought not to be so strong as for salted and fresh calf- 
skins. 

I use this method of softening dry skins during about 
eight or nine months in the year, but when the tempe- 
rature falls, my remedy is found in my wells of water. 
It is very rare that in a tannery one has not one pit 
unoccupied ; availing myself of this pit, I pile in it as 
many dry calf-skins as it can hold, and having covered 
them with heavy stones, set my pump in motion, and, 
instead of sending the water into the reservoir, direct it 
all warm into the pit where the skins are. I jB.ll this 
pit with water, place three or four poles over it, and 
carefully cover the whole with empty bags in such a 
manner as to exclude the air as far as possible. This 
done, I wait 48 hours for the light skins and 62 for the 
heavy. The water in the pit undergoes a partial 
fermentation, and at the end of this time the calf-skins, 
perfectly restored, may receive the action of the stretch- 
ing-iron. 

Dry Calf-sldns from Foreign Countries. — This class of 
skins is of Eastern production ; they come from Madras, 
Calcutta, Java, etc. etc. In France few of these skins 
are tanned, but in England and Germany considerable 
quantities are manufactured. 

To soften them I put them to soak in my vat for 
three or four days, and then withdraw and pile them 
up. When well drained, I give them heavy blows with 
the iron ; the water worker by the strength of his arm 
must tear away the fatty tissues, the thin skin which 
envelops the hide; he thus frees it, breaks down its 
contractility, and expands it one-third. When this work 
is done intelligently and boldly, it may be taken for 
granted that the skins will be well softened. I replace 
them in clean water and leave them there 24 or 48 



300 TANNING. 

hours, according to the season of the year; they are then 
worked on the hair side, and in the direction that the 
hair runs. This done, they are piled one above another, 
the best on the top, and the following solution is applied : 
For about 100 skins, weighing from 6 to 8 lbs. each, I take 
a cask holding about 50 galls., fill it two-thirds full of 
water, and throw in some good lime so as to make it 
boil for a time. While still warm, add 4 \ps. of orpi- 
ment, mix the whole, and let it cool. I proceed as 
follows : To the end of an old broom I tie a stout piece 
of linen canvas, and soak this mop in the liquid, and 
make an application of it to the hair of the skin. 
When well smeared, I bend it double, as one would a 
hide in salting it, and deposit it in a vault constructed 
for the purpose. The same course is pursued with all 
the skins, taking care to pile them in the vat, in the best 
possible manner, and when the last is reached, I pour 
the remainder of the solution over all the skins, so as to 
cover them. They are thus left for three days ; on the 
fourth they are withdrawn from the vat, and I rinse 
them in running water; I leave them to drain and place 
them for 24 hours on a solid platform in order to have 
them swell a little. At the end of this time I prepare 
for the 7'iver ivork. 

River Work. — The river work must be arranged so 
that the men lose the least possible time in taking out 
and replacing in the tubs the skins that they are making. 

Three tubs are necessary to five or six men working 
with a bench ; these tubs should be of a capacity of from 
375 to 400 gls. each, and the water should be introduced 
and drained off rapidly. 

The working benches are four and a half feet long, 
and they are all covered with a heavy plating of zinc, 



TANNING OF CALF-SKINS. 301 

giving an even surface, in order to facilitate operations, 
and to avoid breaks on the hair side, and knife cuts. 

The sheet of zinc is three feet long by two feet broad , 
and the bench is arched about seven inches. 

The zinc is fastened down by round-headed nails well 
driven in ; it should not reach the head^of the table, but 
about one inch lower, for the following reason : It oftens 
happens in working, that one is obliged to lay from 20 
to 25 calf-skins on a table to drain off', and to leave them 
there during several hours. And I have noticed that 
the undermost skin having the hair side next the border 
of the head of the table becomes strongly marked with 
a curve in the neck, and that this impress cannot be 
effaced either in the tanning or currying. The hair 
side at this spot became like parchment, and would not 
absorb the tannin. I looked and attributed this to the 
ridges of my tables. I brought my sheet of zinc one 
inch lower, and from that time I found no more wrinkles 
on the hair side of my skins. 

The table for rounding off" skins, and for thinning the 
necks is broader, and less arched than the other ; it is 
lens shaped. This facilitates the work of the knife, for 
by having a broader surface, the edge is less liable to 
make flaws, and the work progresses more rapidly, as the 
operator is not forced to change the position of his calf- 
skins so often, and when he reduces a throat or a head, he 
does so in a more uniform manner. 

The tools we use are: — 

1st. A, knife having a blade one and a half foot long, 
and provided at either end with convenient handles. 

2d. A tanner's knife with a strong handle ; the blade 
should be 13 inches long, and the curve nearly one inch. 

3d. A smoothing stone, having the stone part 11 
inches long, fixed in a holder or perforated iron, and held 



302 TANNING. 

in its place by iron rivets. Its curvature should be 
about one inch, and the handles should be strong and 
solid. 

It is necessary that each workman should have a 
double set of tools, namely, two No. 1 knives, one lighter 
than the other, and that most used necessarily becomes 
the lighter of the two ; then two knives No. 2, one to depi- 
late and work on the hair side, another to flesh and work 
the skins ; one good smoothing is sufficient. 

Operation First. — The first operation is the depilation. 
In order to depilate freshly slaughtered calf-skins, I place 
on the table two skins as substratum ; for medium skins 
three, and four for middle skins. 

To avoid scratches and to make, the action of the knife 
easier, the workman must give great care to the edge, and 
leave no trace of hair upon them ; then I place them in 
water, and rinse them. 

Next a skilful workman removes the necks ; he cuts 
the navels and nipples, trims the rump and the tail, 
going entirely around the skin, and reaches the throat. 

After this operation the skins are folded crossways, 
starting from the lump on the shoulder. In working 
fresh slaughtered hides I lay them on a bare table, but 
for small medium sized or thin skins I lay two skins 
underneath, to avoid breaking the hair side. 

To execute this operation well, short quick strokes 
should be given with the knife, allowing the edge to cut 
as little as possible. The work should be sharply and 
briskly done upon the cripper, where the nerve of the 
skin should be entirely crushed, but the hinder flanks 
and towards the breasts should be passed over lightly, 
without even attempting to take off the tissue covering 
these parts. The neck should be treated carefully, and 



TANNING OF CALF-SKINS. 303 

the throats and heads, when the skins have them, should 
be briskly worked. By pursuing this course the nerves 
of the calf-skins are crushed on the nervous parts, and 
the weak or hollow spots are spared. After the skins 
have all undergone this process I soak them six hours in 
a tub of clean water. 

I next give them a counter-fleshing, placing two skins 
as a layer on the table. I return them to the water for 
an hour, I then take them out to work them ; for this 
purpose I lay on the table, when the skins are fresh, 
two for foundations, and more if they are small skins. 
I use the stone lightly at first, and then smartly, to rid 
the skins of lime. After using the stone I clean the hair 
side with a knife not too sharply whetted, so as to avoid 
scratches. Then I put the calf-skins again to soak in 
clean water during three or four hours ; at the end of 
this time I take them out in order to work them once 
more on both sides. I then rinse them for the last time, 
and stack them up until I am ready to put them in the 
vats. 

In order that my manner of conducting my dressing, 
and that the whole of my work may be well understood, 
I am obliged to enter into indispensable details. In 
the first place I have to fix a basis of fabrication, and 
determine as clearly as possible how many skins I can 
produce in the course of a year by my method of man- 
agement, the number of operations I must employ, the 
quantity of tan which I require to provide myself with; 
in a word, I have to estimate approximately the price of 
calf-skins when tanned and in the pits. 

I will adopt as a basis the manufacture of 12,000 calf- 
skins per annum, such as they come from the general 
slaughter-house. We reckon these skins, large and me- 
dium together, as weighing, one with the other, 14 i lbs. 



304 TANNING. 

each. We have, therefore, 174,000 lbs. of fresh hides 
to tan, and I use three pounds of tan to tan one pound 
of fresh hide. I shall have to provide myself with 622,000 
lbs. of tan. Beckoning extra heavy skins, which will 
require three layers and a large piece of bark which I 
use in my liquor vats, I may estimate the amount at 
555,000 lbs. of tan to be used during the year. 

Six men at the lime pits and river work will suffice, 
and two men for dressing and to tend the pits, can do 
the work, with the help from time to time of one of the 
men employed in the river work. 

The foreman intrusted with the management of the 
lime pits and with the river work, will work with the 
men and turn the skins. These men will turn 250 calf- 
skins weekly. The foreman dresser will attend to the 
pit, make his liquors and return the skins to the pit. 
A good workman will be assigned to aid him, and as it 
is necessary they understand well each other, it is better 
to leave the choice of the assistant to the foreman. The 
same is done in regard to the foreman of the river work. 

The staff of workmen being well organized, my pits 
well arranged, and my river work complete, we liext 
come to the dressing operation. 

In order to work 1000 calf-skins. monthly we need 26 
vats of oak wood, three feet in depth by five feet and 
one half in diameter. They should be of oak, for the 
edges of a pine vat cannot long stand the daily work to 
which they are subjected. 

Twenty-six vats with 50 calf-skins in each will work 
1300 skins monthly, but as we have vats of large skins, 
only 32 of which can be held, the number becomes re- 
duced to 1000; for before preparing the river work for 
a vatful, we equalize the weight of the skins intended 
for that vat as much as possible. 50 mediam skins 



TANNING OF CALF- SKINS. 305 

weighing 13 lbs. each, make 600 lbs. of fresh hides for 
our vat, and if having calf-skins, only put in 35, 
weighing on an average 17 lbs. each, making 612 lbs. in 
all. It is very important that the contents of the vats 
should be equalized, so that the quantity of tan used in 
each may secure the same result, and in order to reach 
accuracy in this, we weigh all the calf-skins as they 
come from the butcher. The weight is marked on each, 
and before putting a lot to soak, the foreman reckons up 
the aggregate weight, so as not to exceed the limit of 
612 lbs. of fresh hides. 

We give the calf-skins six days in the liquor, and as 
we can put 100 skins in each vat, we therefore require 
six vats for this operation. 

In the handling we put 200 skins together, and leave 
them during one month, consequently we require six 
large vats for this process. They may be built of pine, 
and should be 5i feet in depth and 6i feet broad. 
They are raised 1 J foot above the level of the ground to. 
prevent their being stepped on. The oak vats first 
mentioned should also rise 1^ foot above the ground in 
order to assist the workman who stirs the hides by offer- 
ing a support to his knees on the edges. The risk of 
his pitching in is thus avoided; still, despite this pre- 
caution, it happens that a man will plunge head foremost 
into a vat now and then. This seldom occurs, but it 
has happened, and we have witnessed it. 

We need also 12 racks of solid oak capable of sup- 
porting 100 calf-skins if necessary. We lay the skins 
to drain on the frames when we take them out of the 
vat, to turn over the contents, and to add the quantity 
of tan necessary, when they are returned to the vat. 

The vat is entirely covered with bitumen so as to 
prevent it from rotting at the level of the ground, and 
20 



306 TANNING. 

it is also more clean. If the row of vats is against the 
wall, fill in the intermediate vats and apply bitumen to 
the intervals between them, so that when the skins are 
stirred, the ooze falls back into the vat and is not lost. 

Twenty-six vats in operation for the dressing liquor, 
six vats for the liquors, six large ones for handling, total 
38, to which number two more are added to provide against 
accidents or unforeseen stoppages, making in all 40 vats ; 
and as we require at least four vats to each pit, although 
the calfskins remain longer in the pits than in the vat, 
we have ten pits. They are 6 J feet in depth and 7 feet 
in breadth at the mouth. They will hold about 300 
calf-skins, and we do not have them larger, so as to use 
one a week. This is the result of the general arrange- 
ment of our work, which should progress steadily without 
any stoppage. 

We require also three ooze pits, which are also 6 J feet 
in depth and 7 feet in breadth. We lay in them a double 
flooring of pine pierced with holes for the ooze to filter 
through. Then we have a square upper work of plank 
to hold the pump, which reaches down to the double 
floor. 

In the new pit, which we will designate under the 
name of ooze pit No. 1, we lay from 18 to 24 inches deep 
of coarse bark to support the ooze. In it we place the 
spent tan of the first and second pulverization, and it 
serves to prepare the third vats as well as to aid the 
strength of a feeding vat. At the end of a week this 
becomes pit No. 2 ; its liquor serves to fill my pits. 
At the end of a week this becomes pit No. 3, whose 
strength is almost negative, but which serves to keep 
pit No. 2 from giving out too soon ; it receives the spent 
tan of the last set of pits, and the liquor of the second ; 
in a word it filters the last essence of the spent tan, and 



TANNING OF CALF-SKINS. 307 

it serves also sometimes to modify the strength of pit No. 
1, when we prepare a third vat. At the end of a week 
it becomes totally exhausted; then we have it emptied 
among the spent tan, and use it again as a new pit, and 
thus continually. These ooze pits are of the greatest 
utility, and nothing can be done well without their em- 
ployment. 

Having given a sufficiently full account of the material 
arrangement of the factory, we come now to the operation 
of placing the calf-skins in the vats. 

The third vat, which is the last given, is always a new 
one ; the liquor pit No. 1 serves to prepare it. Its strength 
should be about 3° by the tanninometer, less rather than 
more. It becomes the second vat, and the second vat 
becomes the first, and the first becomes the discharging 
vat. We only use the tanninometer for the third vat, 
for this instrument gives only the strength of the liquor 
when this liquor is free from all gelatine. It would not 
be successfully used to estimate the second vat, whose. 
liquor is already charged with gelatine. The same ap- 
plies with regard to the first and also to the discharging 
vat. The latter is prepared in the following manner : 
Begin by extracting one-half of the spent tan and taste 
it ; its liquor should be barely able to affect the palate, 
and as it is almost always too strong, add to it liquor 
from the pit No. 3, and fill it about I full, so that when 
the calf-skins are placed in it, the whole contents will 
reach to about six inches from the top. Have the calf- 
skins brought up from the river-work. The workman 
takes them one by one and lays them flat in the vats. 
Another man, armed with a long oak wood pole, of the 
length of about five feet, plunges them down the one 
after the other all around the vat. After this operation, 
the same man takes a longer pole, also of oak wood, 8 



308 TANNING. 

feet long, and strong enough not to bend too much under 
the weight of the load. He plunges it along the sides 
and uses it as a lever. From 12 to 15 calf-skins are at 
the end of his pole, which he lowers on the edge of the 
vat, and swings them right and left for about ten 
minutes. 

In this manner he sets the entire contents of the vat 
in motion, and then raising his pole two-thirds, he makes 
it describe half a circle to the left, then raises up his pole 
and lets the skins go, plunges in again, seizing about the 
same number of skins, and continues in this manner 
until he has gone completely around the vat ; then he 
takes a tanner's iron hook, disentangles the skins, equa- 
lizing his vat, and recommences his work with the pole 
and so on during two hours. At the end of this time, 
the calf-skins being well cleaned and well washed, will 
have lost all the lime remaining in them after the river 
work. This operation is complete when the flesh of the 
skin begins to turn black ; then they are promptly taken 
Out by the two men, one fishes for them with the hook, 
and the other takes them one by one, and places them 
on the rack, and this operation being speedily ended, 
they are carried in a wheelbarrow to the first vat, 
which is prepared in advance in the following manner. 

All the spent tan is extracted and tasted, and as its 
juice is always too strong, add to it some barrels from 
the liquor pit No. 3. Fill it two-thirds full, and throw 
the skins into it, in the same manner as in the dischar- 
ging vat, the workman continuing to swing them in the 
same manner. 

The flesh of the skins begins to bleach at the end of 

an hour; throw in 11 lbs. of fine tan of the best quality, 

and continue to stir them. A quarter of an hour later, 

"add a like quantity of tan, and the stirring continues; 



S 



TANNING OF CALF-SKINS. 309 

at the end of another quarter of an hour, examine the 
skins, and you find that a slight grain begins to appear 
on the hair side. Stir them then during i of an hour 
longer, putting in 11 lbs. more of fine tan, and when you 
are certain that the grain is well worked, wishing to ob- 
tain more (so as not to affect the hair side by trying to 
get a premature grain), remove them promptly to the 
rack placed above the grain. Then stir the vat with a 
stirring pole ; the second workman takes a wooden shovel 
and works the liquor, while the other workman stirs. 
Then plunge back the skins again into the vat, one by 
one briskly, taking care to watch that the workman pej;- 
forming this does not drive them to the bottom with the 
first stroke of his pole, after he has plunged a skin about 
half way down, he should change the place of his pole, 
in order to avoid making folds in the skin, or as they 
are called in tanners' language, umbrellas. By beginning 
the stirring operation at six in the morning, it is finished 
by ten o'clock, but leave the skins quiet till noon, then 
take them out and lay on the rack, folded in half from 
the rump to the head, with the hair side inwards. 
Stir the vat again, and plunge the skins in once more, 
adding the while 3 lbs. of tan, of the best quality, ground 
to nut size. At 3 o'clock repeat the operation, except 
that you add no tan, stir the vat briskly, so that the 
froth rises to the top, put the skins in and at six o'clock 
take them out. Stir the vat as usual, and, replacing the 
skins, add 20 lbs. more of the same kind of tan. Above 
the vat is a board painted black, upon which you write 
the day that the skins are first placed in the vat, the 
number of skins contained therein, and score two bars 
to indicate that 88 lbs. of tan have been put in the vat. 
Next day, as soon as the workmen arrive, look at the 
vat, examine the hair side of the skin, the grain begins 



310 TANNING. 

already to be better defined, stir the contents vigor- 
ously, and while the skins are being again plunged into 
the vat, add 22 lbs. of tan, nut size, and then leave the 
skins alone the whole day. At six o'clock in the eve- 
ning raise the vat, and proceed in the same manner as 
before, but in replacing the skins in the vat, add 22 lbs. 
of tan. Next day raise the skins again, and add 20 lbs. 
then, and 20 lbs. more when the skins are replaced in the 
vat, stirring the while. Next day the operation is repeat- 
ed, after which they are allowed to remain undisturbed 
during four entire days. The first vat has taken about 
220 lbs. but gradually, so that the grain of the skins 
cannot be affected. Throw out the contents of the dis- 
charging vat, and take care not to have it put into the 
liquor pits, for this liquor contains too much lime and 
gelatinous matter; this liquid would injure the purity of 
the liquor pits. 

In many tanneries the stirring is done with a shovel, 
and in large establishments where there is mechanical 
motive power, the stirring is effected by the agency of 
floating mills in order to economize manual labor; this 
is an improvement, but the floaters should not be abused, 
for if used without caution, they often scrape the skin. 

Upon the ninth day after the skins have been placed 
in the vat, have them taken out and drained on the 
frame one hour. Then prepare the second vat. Have 
all the spent tan which it holds taken out in order to 
assure the strength of its liquor. Taste it and add 
almost always two pailfuls of liquor of the pit No. 1, 
and one pailful of the pit No. 3 or No. 2, according as it 
is more or less to the required degree. In order to aid 
the estimate, take care to taste the liquor of the first 
vat, and raise the strength of the second about one de- 
gree above the first. Have 22 lbs. of tan, nut size, 



TANNING OF CALF-SKINS. 311 

thrown into it, and stir it strongly for five minutes; then 
have the skins brought to the frame above No. 2 ; agi- 
tate its contents again, and do not wait before putting 
in the skins for the liquor to become still, on the con- 
trary put them in quickly, and after about two-thirds of 
thefti are in the vat, throw on about 11 lbs. of tan and 
keep on. When the last skin is reached, two men pack 
the skins well down on the bottom of the vat, so as to 
exclude the air, and then throw upon them the 11 lbs. 
of tan remaining. This operation is repeated each 
morning for four days, adding each time 44 lbs. of 
coarse tan of the best quality; and take care each day 
to have the skins drained for one hour on the frame, 
between the time of taking out and of replacing them. 
The day that the operation is begun, mark on the board 
the number of skins placed in the vat, and the quan- 
tity of tan put in, and after the fourth day, leave them 
quiet for four days in summer and six in winter. The 
skins therefore remain in the second vat during eight 
days in summer and ten day's in winter. Each day exa- 
mine the progress made by the skins. If they rise too 
much, diminish the quantity of tan; if, on the contrary, 
the skins seem to be sinking down, put in 20 lbs. of fine 
tan, and often even a bucketful of liquor from the vat 
No. 1. This is a matter of practice, and too much care 
cannot be given to the skins while in the vats. The tan- 
ner should devote each forenoon to this important matter. 
In the second vat use about 175 lbs. of coarse tan, nut 
size, and of the best quality, which will be sufficient if 
the tan is good. The ninth or the tenth day prepare 
the third vat with the liquor of the pit No. 1. Fill it 
only half full, and its strength should be about three 
degrees by the tanninometer. If it is stronger than that, 
reduce it, and if inferior, throw in 20 lbs. of fine tan, then 



312 TANNING. 

let the contents be stirred about ten minutes. Next 
empty the second vat and let the skins drain off for two 
hours, when they are placed on the frame of the third vat, 
which is stirred again, and 22 lbs. of coarse tan are added. 
Then put in the skins briskly, in the same manner fol- 
lowed for the previous vat. During four days, opA-ate 
in the same way, putting 44 lbs. of tan into the vat each 
day, and the fourth day leave them quiet. This vat 
takes also about 175 lbs. Thus the preparation of from 
610 to 620 lbs. of fresh slaughtered skins, has taken, 
with the aid of the liquor pits, about one lb. of tan to 
every pound of fresh hides. The work goes on gradually, 
the hair side of the skins remains soft, the grain comes 
out more and more each day, the texture of the skin is 
slowly and progressively penetrated with the tannin. 
The hair side becomes as white as milk, the skins have 
acquired a certain firmness, the necks and flanks are full, 
and nothing more is requisite. Being satisfied now as 
to the result, leave them quiet for six days, taking care 
that the liquor does not ris'e above the vat, for the fer- 
mentation that takes place therein is often so active that 
it requires to be looked to daily. 

In order to prepare a vatful of dry calf-skins with the 
hair on, equal to the vatfuls of fresh calf-skins, put in 
from 440 to 450 lbs. of skins; for 50 lbs. of fresh skins 
do not give more than 20 lbs. of skins thoroughly dried. 
Treat them in very nearly the same manner as the fresh 
calf-skins, but have them stirred an hour longer, as the 
grain of a dried calf-skin comes out much less readily 
than that, of a green skin, and take great precautions 
that the grain may not be affected, which, having been 
dried, already contracts more readily under the action of 
the tannin. Pursue the same plan for Calcutta and 
Java kips. Put in 55 lbs. of skins to each vatful, for 



TANNING OF CALF-SKINS. 313 

kips before they are dried receive a preliminary pre- 
paration, which makes them much more difficult to 
moisten than ordinary skins. 

The action of the orpiment used to depilate them 
speedily has softened the flesh side a little, and this 
grain being more tender requires most careful treatment 
in the vat process. In this manner kips have been 
dressed, having a grain as soft as that of green calf-skins, 
but the work is slower and requires constant watching. 

The calf-skins having been long enough in the vat, 
take measures next for the treatment with ooze. For 
this purpose clean the vat into which you intend to place 
them and turn into it the liquor of the vat No. 2. Put 
about six inches of this liquor at the bottom, and have 
the two No. 3 vatfuls raised, those which you propose 
to use about three hours in advance, so that the liquor 
may thoroughly drain off. Moisten about four hundred 
and seventy-five pounds of fine tan of the best quality- 
This tan you throw in, a handful at a time, upon the 
skins as they are placed in layers in their liquor. It is 
necessary that this tan should be lightly sprinkled with 
water in order that none of it may be wasted, and so 
that one may be able to see clearly the bottom of the 
vat. If it were not moistened, the dust, the flour of the 
bark would be lost, and the men would be incommoded 
by it in their work. 

All these precautions having been taken, have the 
skins brought close to the vat on a wheelbarrow, w^here 
you take them up one by one. The first workman takes 
them up by the hind legs, and casts them with the hair 
side upwards upon the liquor which covers the bottom 
of the vat. The second workman, who is provided with 
a pole, stretches out the fee.t or neck which may have 
doubled under in throwing them in; then the two 



314 TANNING. 

together, each with a pole, push the skins squarely down 
into the liquor. They then throw in three or four hand- 
fuls of bark, seize another skin, and the same operation 
is gone through with each skin. When the liquor be- 
comes all absorbed have more poured in, so that the 
skins are always floating and yet as compact as possible. 
Care should be taken not to pour in too« great a quantity 
of liquor; this is very important, for with the commence- 
ment of this operation the skins having floated sufficiently 
in the three vats, should begin to draw together, other- 
wise the fibrin of the skin will become too soft and weak. 
For this stage of the process use about four hundred and 
seventy-five pounds of fine tan of the best quality, this 
quantity being sufficient for the fifteen days that the 
skins are to remain in the vat. When this work is com- 
plete have about five or six inches of spent tan laid upon 
the pile so as to keep the skins squarely in the vat ; for 
without this precaution, the work of fermentation going 
on, the skins would rise up and get out of the liquor, and 
often in half a day they would have spots on the portion 
of the grain exposed to the air, and such stains can never 
be eflaced. 

We have said that the skins are left in for fifteen 
days. At the end of this period have two vatfuls taken 
out and rinsed in good liquor, and prepare them for the 
next process, after allowing them to drain for three or 
four hours. This is how to proceed in that operation 
which is done with the object of giving a body to the 
skins before placing them in the pits, and in order to 
thoroughly tan the grain side of the calf-skins. In order 
to secure a white and soft grain, that will not change 
color in currying, this grain should be tanned entirely 
through, before replacing the skins in the pits; and this is 
the reason why the skins are placed in a half floating 



TANNING OF CALF-SKINS. 315 

pit with the grain upward, taking care to use only very fine 
bark, so as not to dimple the grain, which is yet tender 
and which has to undergo a certain amount of pressure 
in the next operation. ^ 

After having had the large vat, in which it is intended 
to place the calfskins of the two liquor vats carefully 
cleansed, put in the bottom of this vat about two inches 
of fine spent tan, then take a skin, and throw it quite 
flat with the grain side upwards, upon this layer of bark ; 
the men spread out this skin with their poles, making it 
lay quite flat, so as to make the least creases possible, 
and then they throw handfuls of tan over it, especially 
upon the centre of the body and the neck, so that the 
grain on the flanks may be but slightly covered, but the 
body of the skins well covered. Each skin has the same 
done to it, and in order that the layers may have an 
equal depth, have the tail parts turned towards the walls 
of the pits, which equalizes and regulates its strength. 
This operation being ended, when you come to the last 
skin, have it laid with the grain underneath. Select 
a latge skin for the last, and take care to cover the flesh 
side well with bark. The skins should not entirely 
fill up the vat; there should remain a space of at least 
from ten to twelve inches from the surface of the upper- 
most skin to the rim of the vat, and for this reason give 
to the contents of the pit no other pressure than that of 
their own weight, and the weight of about six inches of 
spent tan placed at the top it. In supplying this vat 
with juice from pit No. 1, lay canvas upon the spent 
tan, so that the liquor when poured in may not disturb 
the bark. Filter gently and gradually; the liquor pene- 
trates the interior, and its weight makes the contents rise 
slightly, and the skins bear themselves up. At the end 
of a day or two, after fermentation has begun, it often 



316 TANNING. 

happens that the whole mass rises from ten to twelve 
inches, therefore if the vat is too full the liquor will 
run over and be lost. For this reason take the precau- 
tion not to fill the vat clear up to the rim, and do not 
place any weight in it, because it is necessary to have 
the skins float a little. By employing a heavy pressure, 
as is done with skins relaid in the pits, the tan would 
imprint itself upon the grain of the skins which would 
create difficulties subsequently in the currying process. 
Use no more tan for this operation than in that preced- 
ing it, but the liquor used to darken the skins is much 
superior. Then, again, use a lesser "quantity of bark, 
which, however, contains necessarily more tannin prin- 
ciple in this operation than that which is used for the 
liquor vats. The work goes on progressively and the 
skins grow more and more compact. During' this pro- 
cess the saturation of the grain is completed, without its 
becoming hard, for one of the most important points is 
to tan the grain thoroughly without rendering it dry, 
and above all things, if it is hoped to curry well, the 
grain should be soft. * 

Leave the skins in this for one month. This time is 
enough; they would gain nothing by being left longer. 
It must be well understood that each time that you take 
a lot of skins out of the vats, the liquor and the spent 
tan contained in these vats are removed to the liquor 
vat No. 3. Nothing should be lost in the work. 

Treatment with Strong Liquors. 

Upon this stage of the operation of tanning we will 
amplify a little. 

After a month in the pit, the calf-skins are again taken 
up; the grain side is tanned, it is white and well satu- 
rated with the tanning material, and since the operations 



TANNING OF CALF-SKINS. 317 

of working, of coloring, and of saturating with the liquors 
succeeded each other without interruption, the grain side 
of the skin almost vanishes under the pressure of the 
nail. It is important to guard against hardening the 
skins by the employment of too strong ooze, and in 
order to avoid this, wash and rinse them in pit No. 3. 
Then lay them together in pairs, always with the grain 
side within and let them drip upon the beam for twenty- 
four hours. Now prepare the tanning pit and cover the 
bottom with a layer of spent tan two inches deep. For 
the middle layers for tanning the skins employ as much 
bark as possible o"f the first quality. Six hundred and 
fifty or eight hundred and seventy-five pounds of this 
are moistened with good tanning liquor and are carefully 
mixed. The moistened mass is put in as small a compass 
as possible in order to obtain for it a greater fermenta- 
tion in the pit. In every one of the pits there is a box 
made of boards, which serves in watering the pits to pre- 
vent the bark wath which the skins are covered from 
being washed about, and at the same time, its outlet is 
serviceable in ascertaining whether there is sufficient 
ooze in the pit. For eight days be careful to see that 
the pits are sufficiently watered and that they have not 
lost any tanning liquor. This is necessary, and by ob- 
serving it, you never have pits in which the upper skins 
become dry, and heat, and become greasy on this ac- 
count. 

When all these preparations are made, the workman 
who arranges the skins descends into the vat. A man 
is detailed to assist him, who hands him the skins over 
the edge of the vat, so that he can take them one after 
another witjiout any further assistance. The carrier 
also brings him the tan in baskets, and the work begins. 
He takes a skin, folds it up, the grain side in, lays it 



318 TANNING. 

flat down, the tail part of the skin directed to the out- 
side of the pit, so the hind shanks of the skin, when they 
bend up together, lie at the extreme edges. In this fold 
he puts a large handful of tan ; he covers the ends of 
the skin of the legs afterwards with another handful of 
tan. The tail part of the skin and the part by the navel 
are also covered with tan. He then turns the fore-shanks 
upon the back of the neck, and puts a handful of tan 
amongst these folds. After this he puts a light covering 
upon the neck and breast, and here he puts a handful 
of tan upon the grain side ; finally he covers the back 
of the neck, and the butcher's cut in the throat with a 
thick layer, for those parts which are the strongest 
have need of a double portion of tan. When one skin 
is prepared in this way, the one who lays them in takes 
another, and lays it in such a way that the succeeding 
layers shall go around the vat in a circle, so that they 
will rise regularly. Thus the thinner part of one layer 
of skins must be upon the thicker part of the layer be- 
neath, by which depressions are avoided, which a bad 
workman, in order to make the layers even, often fills 
up with good tan, to the great detriment of the proprietor, 
who often cannot control this. 

A good arranger of the pits is a valuable workman in 
a tannery, for he makes use of a very dear material. 
When the skin is left in the vat the workman tries it 
with his fingers, and thus knows how to estimate how 
much tan should be applied to it. 

In the first pit, one should not spare the tan, and it 
must be wet with good tan liquor. The liquor of vat 
No. 2 serves for this purpose ; as soon as the workman 
has come to within eight or ten inches from the brim he 
stops laying in, and throws upon the last layer of skins 
a layer of tan about two inches thick, and fills the rest 



TANNING OF CALF-SKINS. 319 

of the eight or ten inches with good spent tan, covers 
this with boards loaded with stones, so as to have a cer- 
tain pressure ; for as soon as this vat is wet, the force 
of the liquor pressing in often raises up the whole. Let 
the calf-skins remain two months in this pit ; at the end 
of this time the tan is spent, and the process of tanning 
will not go on if they remain longer in this pit. Now 
take them out, and beat them with switches, in order 
to get off the spent tan which commonly clings to the 
flesh side. After this the skins will be put to tan again 
in the same way, but on the other side. This time, how- 
ever, less is used than the first time ; the workman 
presses the skins together as hard as he can, and takes 
especial care that the tail part of the skin, and throat, 
and back of the neck, which parts most resist the influ- 
ence of the tanning material are well covered with tan. 
This pit is weighted and wet the same as the first, and 
if one wish, he can finish them up in forty-five days, but 
it is better to let them stand two months. 

If we make a resume of the time of the various ope- 
rations, we have the following : — • 

Depilation, including river work . . .15 days. 

Three vats for coloring . . . . . 30 " 

Soaking ....... 15 

Treatment with liquor ..... 30 

Firstpit 60 

Second pit ....... 60 

The whole 210 

At the end of this time the skins, in case they are 
not treated with too strong ooze in the first and second 
vats, though they must have been sufficiently long in 
the third coloring vat, and likewise in the soaking pit, 
and in the ooze pit, as also in the mixed pit, are com- 
pletely tanned, and ready for currying, unless they have 



320 TANNING. \ 

been neglected between these successive operations, and 
they are very tender, soft, and clean from grain. 

A calfskin for dressing should be tanned with great 
care. Should you leave the calf-skins three or four 
months in every pit, and neglect to lay them down 
flat, or to put them carefully in pairs, the grain side 
within, they would become hard. The grain side of 
this skin would be too brittle for dressing; the nerve of 
the skin would be brought up too sharp, and it would 
be impossible for the dresser to make a soft skin of 
it; blood vein would hinder the table worker, and 
make it too hard for finishing upon the table. In order 
to soften it sufficiently a great quantity of oil, tallow, 
and.degras must be employed ; the grain side will assume 
a brownish color like oiled cowhide ; and when this grain 
side is compressed it will tear and spring upon the pres- 
sure ; in stretching the pushing iron will stick fast in 
the texture of the substance which has acquired a too 
strong power of resistance, and the workman will not 
get on well. 

To get a fine and good dressing, therefore, the calf-skin 
must be well filled with tanning material, but only 
with the right quantity. If it is too little tanned, it does 
not take up the particles of fatty matters which are sup- 
plied for it in dressing, does not gain in weight, for it 
grows then too much in finishing, and because the texture 
of the latter is not sufficiently saturated with the tanning 
matter it becomes fibrous in skinning. Consequently we 
get skins that are fiat and full of cavities upon the neck 
pieces and upon the grain side; even more, we obtain a 
grain side which, in eight to fifteen days after it is 
curried, changes its color. The same thing happens if 
they are too strongly saturated with the tanning material ; 
they remain hard, and show an enormous weight. 



TANNING OF CALF-SKINS. 321 

Seven months' tanning, well carried on, is sufficient for 
middling calf-skins of from twelve to fourteen pounds 
without head; from eight to ten months for large calf- 
skins that we put in the pit a third time. If the tanning 
is extended beyond this space of time, provided, always, 
that the operations are carried on in proper succession, 
little cow-hides are produced and consequently a bad 
material for dressing because it is too hard. 

A good currier recognizes all these wants when he has 
to dress a calf-skin tanned in a defective manner. By the 
employment of great carefulness he may indeed restore 
it so as to make it passable ; but he can never make from 
it a skin of the first quality. Therefore if one tans for 
his own dressing he must follow the simple method which 
we lay down as far as possible, and he can then be sure 
of obtaining magnificent results. 

Dressing. 

Have the calf-skins taken from the pits in which they 
have been treated the second or third time with tan, and 
have them beaten with switches to clear off the tan which 
■ clings to the flesh side. Then have them brought up 
upon dry ground in order to dry them in the air. In great 
manufactories in which the arrangements are complete, 
from one hundred to one hundred and fifty skins are 
brought under a hydraulic press and are dried uniformly 
in a moment. By this much hard labor is saved, and 
the operation answers nearly the same purpose as drying 
in the air; it is to be preferred, even, because the calf- 
skins which are laid out to dry in the air need a careful 
watching that the neck-piece and the extremities may 
have the same degree of dryness as the rest; negligent 
workmen often let the extremities become dry and then 
moisten them up again. This carelessness injures the 
21 



322 TANNING. 

quality of the parts of the skin dried first. In the 
treatment with oil it happens if the workman does not 
take great care that the oil will too freely penetrate those 
parts from which the tanning liquor has not heen evapo- 
rated by the action of the air ; great attention must be 
paid to this so that the calf-skin may dry uniformly in 
all its parts. When the calf-skins have dried in the air, 
they are spread out and then stacked up in a pile. An 
apprentice takes a hard brush and goes over both sides 
of every skin and then it goes into the hands of the 
currier. 



CHAPTER XLVII. 

TANNING OF GOAT AND SHEEP-SKINS. 

Goat and sheep-skins are used by tanners to manufac- 
ture morocco. Owing to the scarcity of goats, the tanners 
use very few fresh skins, the supply being drawn from 
Switzerland, Germany, Africa, the East Indies, and Asia 
Minor. As imported they are dried and covered with 
hair; they require breaking and softening, which is done 
by soaking them several days in water, treading them 
under feet, rinsing, and scraping them on the flesh side 
to produce evenness. They are then passed through 
three old lime pits, the same precautions being observed 
as in the treatment of calf-skins. The process is continued 
imtil the hair can be easily detached, which generally 
requires about one month, then scrape them on the beam, 
re-immerse in lime milk for two days, and flesh with 
the scraping knife. Goat-skins require more rinsing 
than others, and the operation must be repeated several 
times in running water. Bait the unhaired skins with 



TANNING OF GOAT AND SHEEP-SKINS. 



323 



pigeon's, hen's, or dog's dung, to remove the excess of 
lime. Sometimes bran-water is used as bate. 

The skins, after being scraped, are sewed into bag 
form with the grain side outward, and partly filled with 
a strong solution of sumach; inflate them by the breath, 
close them tightly and throw them into a vat containing 
a shallow depth of weak liquor of sumach, and make 
them float by means of a constant agitation so as to as- 
sure the uniform action of the tanning material through 
the surface of the skin, as represented below. Leave a few 



Fig. 10. 




hours, take out the bags and pile them upon each other 
so as to insure the uniform action of the tan liquor 
through the pores of the skin. 

Eepeat the process with new liquor, then unstitch the 
bags, rinse and scrape them on the beam, and suspend 
them in the drying loft. These crust skins are moist- 
ened, rubbed out smooth with a copper tool upon a 
sloping board, and hung up to dry previous to coloring. 
By this method a goat-skin can be dyed in one day. 

Another method is to steep the skins for several days 
in a fermenting mixture of bran water, scrape them on 
the beam, soak and rinse in clear water. Lime in the 
usual manner; work or rub them over with a tool of 



324 TANNING. 

hard schist to press out the lime ; smooth and soften the 
grain ; full them by agitation in a revolving cask, lined 
inside with pegs, and containing water. 

Tan as above, two lbs. of sumac being required for 
each hide. The French process is the same as the 
above. 

This method , constitutes the preparation of the true 
morocco. The imitation morocco is prepared from sheep- 
shins in the same manner as the above, except that after 
being stripped of wool, they must be subjected to power- 
ful hydrostatic pressure for the expulsion of oleaginous 
matters, which being contained in a large amount would 
otherwise seriously interfere with the tanning. 

Lime them in pits containing thirty-three pounds of 
lime for every dozen skins, and allow them to remain from 
three weeks to a month. Then deprive them of hair ; 
resteep them in the pits for five or six days ; rinse ; beat 
in tubs, and when perfectly clean deposit them in ooze 
for one month. 

When sheep-skins are tanned for common leather, use 
oak bark instead of sumach.. 

The color is imparted in the same manner as cloth is 
dyed by means of a mordant. 

Some dye the skins when they reach the state pre- 
paratory to going into the tan liquor, by sewing them 
together with the grain outwards ; then mordanting, and 
afterwards giving them two immersions of a half-hour 
each in the dye bath. 

The most common method is to take the tanned skins 
as they come from the drying loft ; place two together, 
and rub them exteriorly with a brush containing the 
mordant solution, and applying the color afterwards in 
the same manner. When the dyeing is finished, rinse, 



TANNING OF GOAT AND SHEEP-SKINS. 



325 



drain, spread out ; sponge with oil to preserve the flexi- 
bility, and send to the currier. 

The hlack is imparted by the application of a solution 
of red acetate of iron; crimson, by a mordant of alum, 
or tin salt, and decoction of cochineal ; puce, by mordant 
of alum and decoction of logwood ; hlue, by a solution 
of sulphate of indigo; olive, by a weak solution of copperas 
as a mordant, and decoction of barberry, containing a 
little of the blue bath as coloring liquor ; violet, by the 
consecutive application of a decoction of cochineal and 
weak indigo bath. 

The skiver is a kind of leather made from sheep-skins, 
split while in the state of pelt by machinery. It is 
tanned by sumach in vats, being spread out instead of 
sewn into bag form, as from its lesser thickness it is 
more readily impregnated with the tan material. 

Fig. n. 




The extreme thinness of sheep-skins renders necessary 
a peculiar apparatus, and nice manipulations for its bi- 
section. The above figure represents a splitting ma- 



326 TANNING. 

chine, with th^ skin undergoing the process of being 
split. 

This manipulation presents a double advantage ; one 
skin being made into two portions which are then re- 
spectively adapted to uses, for which the original skin, 
on account of its thickness, was not suited. The vibrat- 
ing knife and rollers are so arranged as to give an equal 
thickness to both sections of the skin, or a greater thick- 
ness to one side than to the other, as may be desired. 
The knife acts slowly, but completes the section in about 
two minutes. This kind of leather is used for hat linings, 
pocket-books, box covers, &c. 

The roan is sheep-skin morocco, tanned with sumach, 
but wanting the grained appearance of true morocco, 
which is imparted by the grooved roller in the finishing. 

Bleaching of Goat-shins. 

Bleaching goat-skins in winter, by natural means, is 
a difficult and tedious operation, which can be materially 
shortened by the employment of chemical bleaching 
means. Sulphurous acid is usually used for this purpose, 
but a better result can be obtained by the careful use of 
chloride of lime, which being sufficiently^ diluted and 
completely neutralized, will bleach skins perfectly in 
two days. The solution is thus prepared. Treat two 
pounds of chloride of lime by twenty pounds of water ; 
let stand some time, stirring frequently ; when the liquid 
has become quite clear mix with it 2i pounds of glauber 
salt dissolved in water. Leave to settle ; decant the clear 
liquor, and lay the skins in until entirely bleached, 
which takes about two days. Rinse the skins well in 
water. They could be softened and rendered pliable by 
placing them in a lukewarm soap bath, both prepared 
from white soft soap. 



TANNING OF GOAT AND SHEEP-SKINS. 327 

Coloring of Whole Sheep-shins. 

At the first industrial exhibition held in London in 
1851, there were exhibited whole sheep-skins sent from 
various places and beautifully and durably colored in the 
principal colors that can be brought out on wool, and a 
path has been opened to their use as rugs, carriage mats, 
and many other purposes, where such soft and long- 
haired sheep-skins, dyed to present a handsome appear- 
ance, can be used. The handsomest specimens, as far as 
cleanness and beauty of color are concerned, were un- 
doubtedly sent for exhibition, first of all from the Lon- 
don establishments, and then from Paris and Brussels 
houses. 

The mode of djdng the skins above named must have 
been a special coloring method, for the wool showed a 
uniform color even to the hide, and was at the same 
time perfectly firm. The method of stretching the skin 
and then brushing it over with hot dye-stuffs, a mode 
that furriers now and then follow, could not have been 
employed in this case, as such can be easily recognized ; 
although there is very little difficulty in dyeing wool, 
there is a great deal of dyeing entire skins, where the 
hide, the leather upon which the single wool fibres grow 
firmly, cannot stand the high temperature of the bath 
necessary to the dyeing process, and must not therefore 
be placed in it. 

As the matter was one of general interest, efforts were 
made at the time in London to discover the mode of 
operation, which was kept secret in some degrees, and 
after many useless attempts the whole simple method 
became known. 

We communicate this method, although twelve years 
have since elapsed, partly because these whole dyed 



328 TANNING. , 

sheep-skins created a great sensation in the trade, and 
jet the method of coloring them is almost unknown, and 
again because the question is brought up in a German 
paper, which copied it from an old number of the Muster 
Zeitung. 

Long-haired sheep-skins, having the hair two, three, 
or four inches long, are usually dressed by white tanners 
and furriers by the ordinary process, then cleansed and 
brought wet to be dyed. For this purpose they are 
stretched upon a suitable board and tacked to it with 
small nails, the flesh side downwards ; and in order to 
make them adhere well, both the skin and the board are 
previously wet, thereby securing a very firm and uni- 
form level. The board is provided on the under side 
with transverse pieces which prevent it from warping 
under the dampness, it being vitally requisite to have a 
perfectly level board. Besides this the four corners are 
furnished with rings to which are attached four slender 
chains of equal length, the ends of which come together 
in another ring at the centre (as in a weighing scale, 
only the chains are shorter in proportion), and to this 
central ring is attached another chain which is wound 
around a roller or pulley, so that the board remains in a 
horizontal position, and can be raised or lowered at will. 
After the skin is thus stretched the wool hangs down on 
the under side. This is the preparation for dyeing. 

The coloring itself is done in flat boxes which should 
be larger than the board and 12 inches in depth. They 
are made of copper, and can be tinned if requisite, and 
they have a double bottom that they may be heated 
by steam. The boxes are to be filled with water 
mixed with wool refuse, and the dye-stufl" according to 
the nature of the color to be produced. The dye-stuff 
should be quite concentrated in order that the hair may 



MOROCCO LEATHER DRESSING. 329 

not remain over long in the bath ; then the vessel should 
be heated by steam until it seethes, that is, as high as 
to avoid the bubblings of the contents. 

The pulley above referred to should be immediately 
over the vessel, so that the board can be raised or low- 
ered by the single chain. The board should be lowered 
at the surface of the liquid for a moment, to give a lustre 
to the leather, then let into it and then draw out in 
order to color only the wool, which is soon accomplished. 
The liquor should be kept hot, not in a state of ebul- 
lition, but simmering only ; and the water turned into 
steam should be made good in exact proportion. After 
the color develops itself rinse and dry the skins. 

Every wool dyer can employ this mode of coloring 
with an ordinary kettle, if he takes care to observe the 
main points. They are a uniform stretching of the skin, 
a horizontal and level immersion in the liquor, a gently 
simmering, not bubbling color bath, made rather strong, 
and a restitution of the water changed to steam. The 
leading colors are deep scarlet, yellow, green, bronze, 
Saxony, blue, orange, brown, black, etc. 



CHAPTER XLVIII. 

MOROCCO LEATHER DRESSING— CORDOVAN LEATHER. 

Morocco Leather Dressing, 

Although enamel oil cloth, having its surface finished 
to imitate morocco leather, has come into very extensive 
use during the past ten years, still it does not seem to 
have injured the manufacture of the genuine article. 
Morocco dressing establishments are still increasing in 
number and extent. Real morocco leather is made of 



330 TANNING. 

tanned goat-skin, but the term is now applied also to 
tanned sheep-skin, which is colored, and dressed with a 
polished and corded surface in imitation of morocco. 
The manufacture of sheep-skin into colored leather is car- 
ried on extensively in Albany, N. Y., by the old firm of 
A. Williamson and sons. In this establishment, colored 
sheep-skin is principally used for shoe bindings, and the 
majority of the pelts are obtained green from sheep and 
lambs slaughtered in the vicinity. About 100,000 skins 
are dressed annually, and from this about half a million 
pounds of wool are obtained and sold. 

The first process through which they are made to pass 
is that of soaking and softening by water, to fit them to 
receive the unh airing preparation. Formerly, hydrated 
lime was sprinkled in the inside of each pelt ; it was 
then folded over with the wool side out, and laid down 
on the floor, sometimes called the int. In this manner 
a whole pile or heap was made, and a heating action 
was engendered, by which the roots of the wool were 
loosened, so that the fleece could be easily pulled or 
scraped off on a table afterwards. This method of loos- 
ening the roots of the wool was tedious, occupying seve- 
ral days to complete, and the skins required constant 
watching, as they were liable to overheat and injury, 
both to the wool and the gelatinous tissue. This was 
especially the case in warm weather ; but a remedy for 
this trouble and these ills was lately introduced by Mr. 
Williamson, and is one of the most important improve- 
ments made for many years in this art. This is effected 
by a calcined OTpiment compound which they import. 
It is made up into a thick creamy consistency ; then 
applied to the inside of the skins, which are folded over, 
wool side out, and laid in a heap. In twenty-four hours 
the skins can be deprived of their wool, and if they have 



MOROCCO LEATHER DRESSING. 331 

to lie longer no injury will result. In all cases the de- 
pilatory action is certain without injury to wool or skin 
tissue.* 

The next operation is that of washing the skins prior 
to unrolling them. This latter operation is executed by 
placing them upon an inclined bench, and rubbing off 
the wool with a blunt tool. The flesh side of the skin 
is also scraped to remove slime and loose flesh ; after 
which they are ready for the liming operation. They 
are now placed in vats containing milk of lime, in which 
they are treated for about two weeks. 

The next operation consists in passing the skins 
through a bath of hen or pigeon manure mixed with 
water, which softens them. After this they are washed, 
and passed through a bath of dilute sulphuric acid, 
which neutralizes all the lime that may remain in 
the pores of the skin. After this they are dipped into 
a solution of common salt; sewed up at the edges with 
the grain side out, to form bags, partly filled with tan- 
ning liquor, inflated and tied. They are now placed in 
a tub containing an extract of Sicily sumach, in which 
they float, and are kept in constant motion for several 
hours, and when they have absorbed a sufficient amount 
of tannic acid they are taken out, drained, and rinsed ; 
and, if not to be colored, they are ripped out, and dried 
in the atmosphere in sheds constructed for this purpose. 

They are stretched on boards, rubbed out to render 
them smooth, and tacked down, so as to dry without 
wrinkling. These skins are generally filled three times 
with fresh liquor to tan them fully. 

The next operation is that of coloring. If the color 

* Bj referring to Chapter XXVIII., the reader will see that this 
so-called improvement was a process known for a long time, and orpi- 
ment and lime have been the first agents fixed for the depilation. 

. / 



332 TANNING. 

is to be applied topically, by putting it on the surface 
with a sponge, the skins are first dried. If they are to 
be dyed in liquors they are sewed, so as to have the 
grain side out ; then mordanted, and afterwards handled 
in a tub containing the coloring agents. Prussian blue 
color is imparted by handling the skins, first in a dilute 
solution of nitrate of iron for about one hour ; then in a 
warm bath containing yellow prussiate of potash, and a 
little sulphuric acid. A beautiful blue is thus obtained. 
A scarlet is prepared with a mordant of chloride of tin 
and cream tartar ; the red color is afterwards obtained 
by handling them in an extract liquor of cochineal ; purple 
is dyed by applying a cochineal color on the top of a Prus- 
sian blue ; bronze is obtained from a strong extract of log- 
wood and alum. After being dyed the skins are rinsed, 
stretched on boards ; rubbed smoothly down ; tacked 
around their edges, and dried. 

Topical colors are given to the grain surfaces in many 
instances; they simply consist of a strong extract ap- 
plied with a sponge on a piece of cotton cloth ; almost 
any color can thus be put on. A scarlet color is made 
by a topical application of an extract of turmeric upon 
a dyed cochineal red. To enable some of the coloring 
agents to go on evenly, milk and the white of eggs are 
frequently mixed with them. These applications also 
serve to impart a metallic lustre to the surface. Prior 
to rolling, the dyed skins are slightly shaved on the 
wrong side and trimmed at the edges. 

The subsequent finishing operations consist in rolling 
the skins on a table under a small weighted roller having 
a grooved face, and which is attached to a suspended 
arm which the operator moves back and forth until the 
roller has traversed the entire surface. This operation 
imparts a glossy Cordovan surface to the leather. A 



MOROCCO LEATHER DRESSING. 333 

second rolling with the grooves running in an angular 
direction, gives the surface a diamond corded finish, the 
true morocco style. Formerly these skins were all 
finished by hand labor. The operatives stretched them 
on inclined boards, and rubbed over their surface with 
grooved balls of ebony held in the hand. Sometimes 
an extra finish is still imparted in this manner to skins. 
This establishment is to our knowledge the first who 
applied (in this country) aniline dyes on leather. The 
colors thus produced are magnificent. However, we do 
not recommend them, as they have no stability. 

Cordovan Leather. 

Cordovan leather, which takes its name from the city 
of Cordova, in Spain, and of which the original prepara- 
tion is attributed to the Moors, is plain, but handsome, 
with a fine grain, and similar to the morocco which is 
ordinarily tanned with oak bark, nutgalls or sumach. 
The best kinds, especially the yellow Cordovans, are 
brought from the Levant. Those of Spain, France, and 
Hungary are also highly esteemed, and in Germany the 
cities of Dantzic, Lubec, and Leipsic enjoy a reputation 
for like productions. The material used in the manu- 
facture comprises goat-skins, dog-skins, and even hog- 
skins; they are produced of every color and quality, but 
those made from the goat-skins are the best. 

The skins, after having been cleaned and stretched in 
water, are placed in lime pits ; they are then replaced 
in water for a space of from eight to fifteen days, care 
being taken to renew it from time to time, and to work 
the skins by treading upon them with the feet. After a 
lapse of a fortnight a bath is applied composed of water 
and dog's dung, the temperature not being higher than 
that of new-drawn milk ; then a second bath, equally 



334 TANNING. 

composed of water and of wheat-bran. Immediately on 
being taken from the bath the skins are stretched, 
pressed between two boards, and rubbed with kitchen 
salt. They are then immersed in a third bath prepared 
of figs and water. Only skins which it is intended to 
color black are dyed after having been tanned. Black 
leather is tanned in liquor of the extract of oak bark ; 
that of lighter color must be placed in an ooze made up 
of water and the extracts of sumach and nutgalls. 

When the operation of tanning is completed, the 
leather should be withdrawn, taking with it as little 
moisture as possible, and spread in the shade, where 
care should be taken to rub on the bloom with Sesam 
oil before the sides can become perfectly dry. After the 
oil is laid on, the process of drying in the shade may be 
completed, and the skin may be folded on the flesh side. 
When it is desired to give to the Cordovan a rough as- 
pect, the surface may be rubbed off with a dull knife 
immediately after spreading. 

In many parts of Southern Russia, particularly at 
Karaszubazar, a city of the Crimea, of which the Cordo- 
van manufacturers enjoy a high reputation, wormwood 
[artemisia absinthium) is employed to make fast the 
color in the leather. If, for example, it is proposed to 
dye the leather black, a decoction of wormwood is mixed 
with pulverized cochineal, and then alum is added. 

In the island of Cyprus, Cordovans are dyed red in 
the following manner : The skins, generally about fifty 
at a time, are placed in a fig bath ; they are then passed 
into a strong solution of alum heated to a temperature 
equivalent to that of fresh milk; they are afterwards 
strung up on poles to drip, and at length stretched, in 
order to expel as much of the dampness as possible; 
finally, the skins are extended on a table, and after being 



TANNING OF HORSE-HIDES. 335 

uniformly stretched the red color is applied with a cotton 
rag. The coloring matter is prepared by taking ground 
cochineal, and boiling it in soft water in a well-tinned 
kettle, and during the ebullition five ounces of powdered 
alum are added for every five ounces of cochineal, and 
the liquor boils until it has been reduced J or s by eva- 
poration, when it is poured through a filter. The skins 
are coated four or five times with this preparation, and 
after being placed in the tanning liquor, are submitted 
to the operation of dressing. 

In Hungary and in Transylvania, where the manu- 
facturers of Cordovan produce goods which are highly 
esteemed for their quality, the red color is laid on in a 
difierent manner. When the skins have been properly 
prepared for the process, they are fastened together by 
couples in the form of bags, care being always taken to 
place the sides to be colored within and facing each 
other, and to leave but one opening. Into this opening 
the warm coloring matter is poured ; the mouth of the 
bag is then tied, and if the color does not readily pene- 
trate all parts of the skins and readily unite with them, 
they are agitated or rolled around. 



CHAPTER XLIX. 

TANNING OF HOESE-HIDES. 

About sixty years ago the tanning of horse-hides was 
considered a problem, but now they are largely converted 
into leather, and they make excellent material for uppers 
and the legs of boots. 

They are lined in the same way as calf-skins, but 
being much thicker they require a longer exposure in the 
tan pits, eight months being necessary. 



836 TANNING. 

Horse-hides can be easily tanned, and transformed into 
excellent leather in fifty days, by the following process :* 
" Soak the skins for one night, and pass them successively 
through three lime pits; let them remain one day in 
each, the fresh pit containing one bushel of lime for 
seven skins. Take out, and wash in running water; 
work them in the usual way on the beam, and pass 
them through the vats, remaining six, eight, and in 
Mdnter, ten days in the first one. During this part of 
the operation take them out, and replace them from 
time to time, as often as eight or ten times daily for the 
first five days. The liquid of the first vat should mark 
0.7° by Baume's areometer; that of the second should 
be 0.9°, and while in this the skins should be taken 
out only once daily. After nine or ten days, remove 
them to the third liquid, which has a density of 1.2 ; 
allow them to remain in for the same length of time ; 
and finally keep them for ten or twelve days in the last 
vat, w^hich marks 2°. During this last period, two baskets 
of fresh tan, weighing 55 lbs., should be daily thrown 
into each vat. 

"After removal from the last vat the skins are 
thoroughly tanned. They are then rubbed upon a 
marble table, first on the flesh, then on the hair sides ; 
half dried upon hooks attached to the ceiling of the 
drying room, and sent slightly moist to the currier. 

"A horse-hide weighing 22 lbs. loses 6^ lbs. by clean- 
ing, but gains 8i lbs. in the tanning." This process is 
very simple, but requires all the attention and care of 
the workmen, and differs from that for other hides, in 
their not being placed at all in pits, and in being sub- 
jected to the action of tannin while floating in liquid. 

* Dumas, "Traite de Chimie Appliqu^e aux Arts." 



TANNING OF THE SKINS OF SHEEPS' LEGS. 337 



CHAPTER L. 

TANNING OP DIFFERENT SKINS. 

The skins of bucks, wolves, elks, dogs, and other ani- 
mals can be tanned as those of goats and sheep. Those 
of lambs, kids, cats, rabbits, and hares, do not require 
exposure to as strong infusion, nor for so great a length 
of time as sheep-skins, while those of hogs, wild boars, 
and bears, are prepared like them. When these skins 
are fresh, and when it is intended to prepare them with 
the hair, the time is considerably lengthened. Human 
skins can be tanned like others. They have more body 
than cow-skins, and are thickest upon the abdomen. 
They require a greater number of limings and of expo- 
sures to the infusions of bark, and they swell up a great 
deal under these operations. 



CHAPTER LI. 

TANNING OF THE SKINS OF SHEEPS' LEGS FOR MAKING 
TUBES WITHOUT SUTURE, FOR COVERING THE CYLIN- 
DERS USED IN COTTON AND WOOL SPINNING. 

A Parisian tanner, M. Delvau, introduced this process, 
which consists in cutting the skin of the sheep's foot 
above the spur, and stripping it off in a manner similar 
to that after which rabbits are uncased. This tube is 
then limed, until the wool falls off, is daubed with oil, 
and curried so as to make it 'of an equal thickness 
through. 
22 



338 TANNING. 

To apply these tubes to the cylinders without suture, 
two burnishing tools are used for spreading them out. 
Each tube, which is made of such a size as to exceed 
the cylinder a little in diameter, is drawn over it, and 
stretched upon it by means of pincers, and the parts which 
pass beyond the ends of the cylinder are folded down, 
smoothed out, and glued over them. These extremities 
are then rubbed with the burnishers, in order to make 
the glue enter the substance of the leather, and they are 
left to dry five or six hours. The shreds of leather are 
then removed, and those parts which project from the 
middle and ends are cut away on a turning lathe. To 
finish the surface and give it lustre, it is well rubbed 
with a hard linen cloth. 

Leather Bottles. 

These bottles are used in France to carry oil and 
wine. Cow-skins are used for this purpose. They are 
dried upon pegs by the butchers, and are then softened 
in lime which has been previously used, and in which 
they remain for eight days. Then they are thrown into 
a fresh lime pit until the hair readily comes ofi*; they 
are cleaned, rinsed, and fleshed after having been cut 
into pieces of the proper shape. Then expose them to 
dry upon a smooth, clean and dry spot of ground, great 
care being observed that this drying takes place uni- 
formly and gradually. When thus deprived of moisture, 
and at the same time preserving all their suppleness, 
they are hung up for a month, and exposed to the direct 
rays of the sun, being taken down and stored at night, 
so that no moisture shall have access to them. 

Before being sewed they are placed in water to allow 
the stretches to be made. These bottles last a long time, 
but liquids kept in them always acquire an unpleasant 
taste. 



RED LEATHER. 339 

CHAPTER LII. 

BED LEATHER. 

The butts used to manufacture this kind of leather are 
imported from Buenos Ayres. Soak them from four to 
five days, deposit them in an old lime vat, extend them 
evenly so they may not wrinkle ; the largest hides being 
cut in half along the line from head to tail. Handle 
repeatedly in this pit for five days, and deposit them in 
a fresh vat where they remain for two or three months; 
handle them twice a week, and add a little fresh lime 
during each of the last five handlings. "When they are 
ready to be fleshed, take them out, rinse them four times 
only partially, so that the lime may not be entirely 
washed out. 

Place the hides in the pit, and stratify them with the 
bark of the root of the evergreen or scarlet oak, which 
has been soaked in water. 

Leave three months in the first pit, place in a second 
one, and expose them to the action of the bark for the 
same length of time, take them out, dry and carry 
them to the currier. Each hide requires about 120 lbs. 
of bark. 

CHAPTER LIII. 

DANISH PROCESS. 

By this process dressing leather may be made in two 
months. 

Soak the hides, flesh and free them from hair, and 
rinse them in the ordinary manner; color them like 



340 TANNING. 

barleyed skins. Sew them into form of bags, leaving an 
aperture about ten inches long, by which you fill them 
with tan and water. Sew those openings, and beat the 
closed sacks in every part, for the purpose of distributing 
their contents equally through j then deposit them in 
pits containing sufficient ooze to completely cover them. 
These pits are 4i feet in depth; the same in breadth, 
and from 8i to 10 i feet long. Place upon the skins 
planks heavily loaded with weights, and press them 
towards the bottom to increase the penetrating power 
of the infusion. To have them equally tanned, remove 
the boards three or four times a week, beat the sacks 
and change their position. 

These skins are supple and pliable, have a finer color 
than strong leather; they ai"^ thinner than those made 
by the ordinary process, owing to their not swelling up 
by the slow process of feeding, and to the pressure to 
which they have been submitted. It is doubtful if the 
durability and other qualities of the product are equal 
to those of leather prepared by more tedious processes. 



CHAPTER LIV. 

CHEMICAL THEORY OF TANNING. 

The operation by which skins are converted into 
leather has been known and practised since the most 
remote antiquity ; but the nature of the tanning prin- 
ciple was unknown before the experiments of Lewis and 
De^^eux, and the experience of Seguin. This latter 
chemist has given the following theory of the art of 
tanning : — 

1st. The skin stripped of its flesh, is a substance which 



CHEMICAL THEORY OF TANNING. 341 

can be easily converted by a convenient process into. an 
animal jelly which, concentrated and dried in the air 
furnishes glue. 

2d. A solution of this latter substance being mixed 
with an infusion of tan, an insoluble precipitate is formed, 
and this precipitate is not susceptible of putrefaction. 

3d. The solution of tan is composed of two distinct 
substances, one precipitates the glue, and is the true 
tanning matter, the other precipitates the proto-sulphate 
of iron without precipitating the solution of glue, and 
produces only the disoxygenation of the skin and of the 
substance which unites the hair to the skin.* 

4th. The operation of tanning is not a simple combi- 
nation of the skin with the principle which precipitates 
the glue, but a combination with the skin disoxygenized 
by the substance, which, in dissolution in the tan has 
the property of precipitating the sulphate of iron. Thus 
all substances to be used to tan ought to have the pro- 
perties of precipitating glue and sulphate of iron. 

5th. The operation of tanning consists, first, in the 
swelling of the skins by an acid principle. Second, a 
disoxygenation by gallic acid. Third, in disoxygenating 
the skin with the same principle, and by this disoxy- 
genation it is in a middle state between glue and skin. 
Fourth, in combining it by this disoxygenation. 

Whatever are the merits of Seguin, and the services 
he has rendered, we cannot but expose all the errors of 
the above theory. 

We persist in looking at the swelling of the skin as 
an effect less chemical than mechanical, which is princi- 
pally due to the interposition of the water, or to the effect 

* Seguin does not speak of the extractive, which, according to Sir 
H. Davy, is necessary to form a flexible and firm leather. 



342 TANNING. 

of the caloric produced by the fermentation. Acids and 
alkalies, as we have said, act only as a means of preserv- 
ing the skin from putrefaction; afterwards they exercise 
a chemical action. Thus the lime with which the interior 
of the skin is saturated, notwithstanding all the wash- 
ings, forms with the tannin a tannate of lime, which 
takes away the suppleness of the leather ; and for this 
reason it is that the lime method is injurious. It is not 
the same with acids. Besides preserving the skin from 
putrefaction, the produced acetic acid reacts on the 
fibrin, softens it and transforms it partly into a trans- 
parent jelly, soluble in boiling water and combining with 
the tannin. Besides this acid, by which the skin is more 
or less saturated, it precipitates the solution of tannin 
and fixes a larger quantity in the leather. This soften- 
ing renders the swelling very easy. However, it can be 
operated without these means, which are in antagonism 
with Seguin's theory. 

We do not agree with Seguin that gallic acid is the 
principal and indispensable agent in tanning. No ex- 
periment has demonstrated the durable disoxygenation 
which he asserts, and which is impossible if we compare 
the respective constituents of gelatine and fibrin. Thus 

Fibrin contains . 12.^1^ per cent, of Oxygen. 

Gelatine " . t^.207 " 

From this we see it is impossible that gallic acid dis- 
oxygenizes the fibrin and transforms it into glue, whilst 
pure gelatine contains nearly one-third more of oxygen. 
If such were the case, gallic acid must oxidize instead of 
disoxygenizing it. We therefore see that this theory is 
inadmissible. Let us now record the experiment : — 

Catechu contains from 48 to bi per cent, of Tannin. 

Tea " " 34 " 40 " 

fferb Bennett " 42 " " " 

Scille " 24 



CHEMICAL THEORY OF TANNING. 343 

These substances, so rich in tannin, are applied with 
success in tanning, while, however, they do not contain a 
particle of gallic acid. Seguin does not mention the 
extractive, however; this substance has some action in 
the tanning, and according to the experiments of Sir H. 
Davy its presence is necessary to form a flexible and 
firm leather, and in some way it may take the place of 
tannin. In England, where tanning material is very 
scarce, they have used the decoction of cicuta; and 
Schwerger has shown by analysis that 100 parts of fresh 
leaves contain 2.73 of extractive without tannin or 
gallic acid. 

To resume, we regard tanning as a combination of five 
principles, fibrin, gelatine, tannin, extractive, and acid. 

1st. Gelatine and fibrin are transformed into a jelly, 
by acetic acid with tannin, extractive and gallic acid. 

2d. In tanning, the epidermis disappears, and no por- 
tions of the skin have been disoxygenized. 

3d. The action of gallic acid is similar to that of 
acetic acid, and its presence is not necessary in the ope- 
ration. 

4th. Extractive, like tannin, unites with the altered 
gelatine and fibrin, and renders leather flexible and 
firm. It is also the principle of their coloration ; thus 
leather tanned with gall is pale, that with oak bark is 
brownish, with catechu is reddish, etc. It is the ex- 
tractive which gives to the leather a brownish color, 
without rendering it insoluble in boiling water. 

5th. Lime forms with tannin a tannate of lime, which 
destroys the suppleness of leather, and renders it dry 
and brittle. 

6 th. Dried skins well tanned increase in weight about 
33 per cent. This increase is due to the fixation of the 
tannin, extractives, gallic acid and a little water. 



344 TANNING. 

7th. In saturated infusions there is less extractive than 
tannin, while in weak infusions the extractive predomi- 
nates. That is the reason why it is necessary to place 
the skins at first in very weak infusions, and, lastly, to 
saturate them, little by little, with tannic acid and ex- 
tractive, so as to have a complete tanning and a more 
supple leather. 

8th. By presenting to the skins strong infusions, the 
leather contains but very little extractive, and is tanned 
only on two surfaces, the centre containing little, so that 
the leather obtained is hard and brittle. 

9th. At last, gallic acid exercises so slight an influence 
on tanning, that Sir H. Davy thinks it is doubtful if 
oak bark contains any. 

Chemical ResearcJies on the Art of Tanning.* 
By M. Knaj)p. 

Every one knows that it is not the skin which is 
w^orked by tanners, but the prepared skin, or the corium, 
or the skin separated, as much as possible, from the 
useless parts by mechanical and chemical treatment. 

The prepared skin, when damp, has the appearance 
of a tissue of a milky color ; seen by the microscope it 
appears to be composed of parallel fibres without color, 
and transparent. 

The transparency and the milky appearance are the 
effects of the dispersion of light. The skin, by drying, 
contracts, assumes a homogeneous appearance, and be- 
comes horned. But by working it it becomes again white 
and pliable, as before the desiccation. 

This change of nature is due to this, when the skin 
dries, the fibres which compose it agglutinate, one on 

* Repertoire de Chimie. 



CHEMICAL THEORY OF TANNING. 345 

the other, exactly as the surfaces of the intestinal skin, 
which composes violin strings ; thus the spaces which 
separate them disappear, and it no longer transmits 
light. 

The object of tannwg is at first to destroy, as much 
as possible, the tendency of the skin to putrefy princi- 
pally, and it is its characteristic function to cause the 
skin, when dry, to remain a fibrous tissue without trans- 
parency, and to remain pliable. Three operations are 
necessary to transform the skin into leather, the anterior 
2'>Teparation, the tanning, and currying. 

The Preparation consists in taking out the flower of 
the epidermis, and the hair which covers it, and the flesh 
of the adhering membranes. The maceration and the 
working are sufficient to prepare the flesh; the treatment 
of the flower requires chemical substances, such as lime, 
sulphurets, etc. 

The modus operandi of these two substances is different. 
Lime acts by rendering the tissue of the epidermis softer, 
which admits of its easy depilation, whilst on the con- 
trary, sulphurets act on the basis of the hair, render it 
milky, so that if a piece of skin is macerated in this re- 
agent, the hair can be taken out only by rubbing it with 
a piece of wood. 

Tanning is generally considered as a chemical opera- 
tion. 

Every one agrees that there is found in the skin an 
immediate principle, which combines with the tannin 
or with tanning substances, and then it is compared to 
gelatine, some even consider the leather as a tannate 
of gelatine. 

The known facts are sufficient to demonstrate how 
far this theory is from the truth. 



346 TANNING. 

At first, acidulated bones, which give gelatine as the 
skin, are not capable of giving a product similar to 
leather, lohatever is the quantity of tannin and the time of 
contact. Then the salts of iron and alumina, which tan 
leather, do not precipitkte the gelatine. At last, grease, 
which tans perfectly well, has no similarity to tannin. 

It may also be said that, generally, when a chemical 
combination takes place, the form disappears; and it is 
sure that, in tanning, not only the texture of the skin 
does not disappear, but is rather developed ; however, 
as in gun-cotton, it will be admitted that the substance 
of the skin can combine, without apparent change, with 
the tannin, as the cotton with the nitric acid. 

A more serious objection is in this known fact, that 
tanning substances, such as alum, can be tahen from the 
sldn hy a sufficiently long ivashirig, then the. skin reappears 
with its primitive character. 

Tannin itself can be taken from the skin. If we take 
a skin which has been immersed in pure tannin and is 
transformed into leather, we can by a weak alkaline 
solution, separate all the tannin, and the skin can be 
tanned again. However, skin which has been tanned 
with tan, and treated by carbonate of soda, loses the 
greater part of the tannin it contains, but it does not 
cease to he leather, as is thc/case with skin tanned with 
pure tannin. It retains a tanning substance peculiar to the 
tan and differing from pure tannin, which the carbonate 
of soda cannot dissolve. Evidently these facts do not 
agree with the theory which sees in tannin a chemical 
action. Mr. Knapp thinks that analytical experiments 
alone can resolve this question. For this purpose he 
takes a prepared and purified skin, dries it in vacuo, and 
operates on a determined weight that he submits to the 
action of tanning dissolutions, and weighs anew after a 



' CHEMICAL THEORY OF TANNING. 347 

thorough washing and drying in vacuum. These experi- 
ments have given the following results. 

Skin immersed in a solution of alum contained, after 
the operation, 8.5 per cent, of additional matter. The 
increase in weight was due only to the incorporation of 
the olum in nature; there is no chemical decomposition 
in this operation. With sulphate of alumina the result 
was the same ; the skin fixed 27.9 per cent, of anhydrous 
sulphate of alumina. The chloride of aluminum acted in 
the same manner; it united without decomposition, and 
the skin contained 29.3 per cent. Acetate of alumina 
gave the same results, and the skin contained 23 per 
cent, of this salt. 

It results from these facts, that not only is it no 
decomposition of the tanning salt, as in acid and basic 
salt as Berzelius thought ; but that the quantities absorbed 
are without relation to their equivalents. The author 
adds that these numbers are not absolute; that they 
vary with circumstances, principally with the concentra- 
tion of the liquids, and that the fixed salt can be taken 
out by washing with pure water. Thus the proportion 
of chloride of alumina after a washing of three days, has 
been reduced from 29.3 per cent, to 3 per cent. 

The corresponding compounds of chrome and iron 
behave in the same manner as the salts of alumina, only 
they are absorbed in less quantity, and they color the 
skin, while the salts of alumina do not. 

Fatty bodies, as sesquioxide salts, will tan. This fact 
alone is in opposition to the idea of a chemical combina- 
tion of the tanning matter with the skin. Nevertheless, 
the author has tried to prove by experiment, if there was 
in the quantity of the bodies absorbed to convert the 
skin into leather, any evidence in favor of the theory 
which he was disputing. He dipped skins into alco- 



348 TANNING. 

holic solutions of stearic and oleic acid; or ethereal 
solutions of fish oils, and he ascertained that the tdn- 
ning was perfect, and that the fatty body was not modified, 
and the absorbed quantity was from 1 to IJ per cent. 
Kesins have acted like greases. This small quantity of 
tanning substance represents only the proportion kept in 
solution by the reagent in which the skin is macerated. 

All the above experiments demonstrate that tanning 
is not a chemical action, and Mr. Knapp has substituted 
for the old theory a more solid one. To this chemist, 
tanning substances have the function of enveloping the 
fibres of the skin, so that their adherence becomes im- 
possible, and that the skin keeps its pliable qualities after 
the desiccation, or at least recovers it by a mechanical 
action ; this is to Jiim the true character of tanning. 
To demonstrate his proposition, he established a series 
of experiments, the object of which was to tan the skin 
ivithout the use of tanning substances. Considering that 
the fibres agglutinate together only when they are pene- 
trated by water, he conceived the idea of putting the 
skin in contact with a liquid (alcohol or ether) which, 
expelling the water by endosmose, takes away from the 
fibres that property of agglutinating together. According 
to his views, he has obtained by the action of alcohol alone, 
a tanned skin very white, and of such a constitution 
that practical men have recognized it as a tanned skin. 
Then this is a true leather without tanning matter, which 
in water becomes again skin, and by the coction is changed 
, into glue. 

This last experiment shows that tanning is not a 
chemical action. When Mr. Knapp speaks of tanning, 
he understands only the conversion of the shins, which in 
drying will hecome horned, into a matter which rernains 
flexible even by desiccation. For the other qualities that 



CHEMICAL THEORY OF TANNING. 349 

leather requires in tanning, such as imputrescibihty, etc., 
they are not absolutely inherent in the nature of the 
leather; they are only relative, and they are obtained at 
variable degrees according to the products obtained, and 
the operations to which the skin is submitted. 

The conclusions of Mr. Knapp's experiments are 
the following: Tanning is not a chemical operation, 
leather is no more tannate of gelatine than tanned skin 
is a combination of gelatine with a sub-sulphate of 
alumina. 

The proof of it is in the following facts : Some ^b- 
stances, which, like skins, can be converted into glue, 
do not give leather. 

Tanning substances are not absorbed by the skin in 
definite proportions. The different tanning salts do not 
unite with the skin in equivalent proportions. 

Tanning salts, and tannin itself, can, by washing, be 
separated from the leather which becomes skin again. 

Fatty bodies which have no similarity to astringent 
compounds, will tan leather. 

Skins may acquire the properties which are given by 
tanning without the use of tanning compounds. 

At last some substances unite with the skin and render 
it imputrescible, and incapable of forming gelatine; with- 
out giving it the qualities of leather. 

According to Mr. Knapp, leather differs from the dry 
skin in this, that in the last the fibres adhere one to the 
other, while in the first they are isolated ; the part of the 
tanning substance is to maintain this isolation. 

The tanning substances surround each fibre instead of 
uniting with it as chemical substances. 

To realize an industrial tanning, you want reagents 
which can be fixed on the fibres of the skin, prevent 
the adhering of these fibres, operate with rapidity, and 



350 ' TANNING. 

give to the skin the required suppleness and the pro- 
perty of resisting putrefaction. These conditions £fre 
partly fulfilled by the use of salts of sesquioxide. 

The tanning action of iron salts has been known for 
a long time, but it has not been much utilized yet. 

Leather tanned with iron salts is often flat, hard, 
and brittle, even when the solutions are the most 
nearly neutral possible. The acid reaction of the salt is 
sufficient to destroy the quality of the leather. It is a 
known fact that an alkaline reaction is favorable to the 
swelling of skins. 

The above experiments have conducted Mr. Knapp 
to the following process : — 

Prepare two baths, one with soap-water, the other 
with a solution of iron, alumina, or chrome. 

The solution of soap must not contain more than 
_i_ or gig- of soap. If hard soap is used (soft soap is bet- 
ter), the bath is kept at 100°. 

Prepare also the solution of tanning-salt, which should 
be one-tenth, with the chloride of iron, which colors the 
skin brown red, or with the chloride of chrome, which 
gives a gray-blue color, or with the chloride of alumina, 
which is colorless. 

Dip the skins in the metallic solutions, stir them, 
draw them, dip them again, and so forth, till they are 
well-penetrated. Forty-eight hours are sufficient to 
obtain this result. 

The skins, being well drained, are thrown into the 
solution of soap. When the reaction is complete, wash 
and dry them. 

This operation is very rapid, and it may be rendered 
more so by substituting alcoholic for aqueous solutions. 

We see that this process, while very dijQferent from 



CHEMICAL THEORY OF TANNING. 351 

tanning, conducts to the same results; is quicker and 
cheaper, and gives a simpler, brighter, and softer skin. 

Tanning can also be obtained by dipping the skin in 
a very weak acidulated water, then in soap water, and 
repeating this operation two or three times till all the 
skin is tanned. Wash and dry. 

In the course of this paper we have spoken of an ex- 
periment consisting in impregnating the skin with an 
alcoholic solution of stearic acid. The author insists on 
that experiment as giving a new and quick process of 
preparation. Leather thus obtained is very flexible, and 
as white as white kid leather ; the grain is fresher and 
brighter. 



352 TANNING. 



SECTION YI. 

IMPROYED PROCESSES. 

In order not to interrupt the series of the operations 
of tanning we think it better to devote a special section 
to the improved processes. We shall make no comment, 
and we leave it to intelligent manufacturers to con- 
sider as our judgment of the different processes we 
describe, that which agrees with what we have before 
expressed. 



CHAPTER LV. 

SEGUIN'S PROCESS. 

The preliminary processes are the same as those of 
others, excepting that after soaking and fleshing, he 
rinses the skins in running water, so as to expose all 
parts to it. He depilates them with lime and deposits 
them in tan juice mixed with ^-J^ or sometimes yoV^ 
part of sulphuric acid. 

For raising, he uses a vat lined with a cement con- 
taining lime and filled with water containing j-^-q-q part 
of sulphuric acid, but he finds that the acid instead' of 
mixing with water combines with the lime. For these 
vats he substitutes wooden tubs and fills them with 
water containing j-^^-q part of sulphuric acid, which in- 
creases to xoVo^j ^"^ ^y t^i® arrangement he was enabled 
to raise skins in forty-eight hours. According to this 



PROCESS OF PREPARING GLOSSED LEATHER. 353 

chemist this raising is not necessary, as he could make ex- 
cellent leather from skins not submitted to this treatment. 

He placed the skins in vats filled with ooze. To ob- 
tain this solution he filled a number of tubs placed in a 
row, with ground tan. In each tub he put a certain 
quantity of water, which filtered through the tan, dis- 
solved its soluble particles, and was received in vessels 
beneath. He passed the liquid of the first vat on the 
second, and so on till the liquid was completely saturated. 
As the two still contained a certain amount of soluble 
material, he treated the tubs until the tan was completely 
exhausted. 

The ski^s being taken from the acid bath, he placed 
them in a very weak infusion of tan and allowed them to 
remain only one or two hours to color the hair sides. He 
then immersed them in a stronger solution, and continued 
thus, increasing each time the strength of the solution 
until the tanning was completed. 



CHAPTER LVI. 

PROCESS OF PREPARING GLOSSED LEATHER BEFORE THE 
TANNING OPERATION. 

This new process of preparation of hides, invented by 
Messrs. Monier and Ray, consists in trampling them 
in a fulling machine, disposed so as to contain any liquid 
put in, and having below holes for the water to run off. 

Details of the Work of Preparation of the Leather. 

Hides. — Soak them for 48 hours in cold water. 
Smelting. — Introduce the hides into the fulling ma- 
chine, which according to the size of the hide will con- 
23 



354 



TANNING. 



tain 8 or 10 or even 16 of them. Trample them for 
half an hour, which is sufficient to render them suffi- 
ciently supple. 

Limmg. — After beating them a few minutes to free 
them from water, put them into the lime vat. the lime 
being of the consistency of thick milk, and in sufficient 
quantity. The hides being thus exposed, beat them for 
four hours, withdraw them, pile them one upon another, 
leave them for five days, the time necessary to warm 
them, and then put them back into the fulling machine 
to clean them. 

Cleaning. — Work them in the fulling machine for 1 i 
hour, take them out and scrape them well. ^ The first 
cleaning not being sufficient to take off all the lime, leave 
them one hour in a water containing ^^-^ of sulphuric 
acid, handling often. Wash them well in running water. 



Descriptio7i of the Apparatus. 
Fig. 72. 




Side elevation. 



PROCESS OF PREPARING GLOSSED LEATHER. 
Fiff. t3. 



355 



r^_ 




eMb 



]A 



i/f 



S=jr :: (f 



'L 




Front view. 
Fig. U. 



n 



ifeji 



:NiO 



^ 



^^^iib 



gijti 



Plan. 

(a). Trough in which the skins are placed. 

{h). Post raised above the trough, and supporting the levers (c) near 
their upper end, where these levers are attached to a piece of wood {d). 

(e). Key to press the post (h) and to give it the necessary inclination. 

(/). Mallets fixed to the lower end of the levers (c), and working 
on the skins, in the hollow part of the trough (a) formed by the curved 
line seen in {g). 



356 TANNING. 

{h). Keys disposed so as to keep the mallets conveniently inclined 
to the form of the curve cj of the trough. 

(i). Other keys having the same uses as the abo^. 

(Jc). Two curved posts, raising above the trough and preventing the 
mallets from swaying. 

(l). Piece of wood joining the posts h at their upper extremity, 

(m). Yertical turnstile with four branches, the axis {n) of which is 
received and turns in the posts k, and is used as a shaft to the ropes 
(o) which keep the mallets suspended. 

(/?). Wheel put in motion by water, its axis {q) carries cams (r)\ 
which by turning let the mallets (/} rise and fall alternately. 

Tanning. — After the cleaning of the hides, and before 
putting them in the tan vats, they are submitted to 
the action of an ordinary press, then they are placed 
in vats filled with tan water, in which they are left for 
six days. 

After six days the leather is pressed again, and is put 
back in the vats containing tan water stronger than the 
above. It is left in for ten days. Press again and cany 
to the pits, where the leather is left two or three months. 



CHAPTER LVII. 

TANNING- WITH MYRTLE ( Vacdnium Myrtilus). 

This process was discovered by a tanner of Bern- 
Cassel, Mr. Rapenius, who found that a superior leather 
could be made by tanning with the myrtle plant. This 
plant is collected in the spring of the year, is dried and 
ground. One hundred pounds of leather require three 
hundred and fifty parts of this substance, while it requires 
six hundred parts of oak bark, and its use saves four 
months of the time generally employed. Leather made 
with it is of a superior quality. Shoes made with it last 



TANNING "WITH GRAPE-SKINS. 357 

two months longer than those made from common 
leather. The skin of the neck becomes as strong and 
elastic as other parts when thus prepared. The myrtle 
should be cut off, and not pulled up by the roots. After 
it is cut it is not injured by water as oak bark, which 
loses by exposure to moisture. 



CHAPTER LYIII. 

TANNING WITH GRAPE-SKINS. 

In 1829, a chemist of Narbonne proposed to substitute 
grape-stalks for oak bark in tanning. His process is 
thus spoken of by Nachette, in i\\Q Journal of Pharmacy. 

"A substitute for oak bark has long been sought for, 
but no one yet has before thought of employing for this 
purpose the stalks and skins of the grape. This chemist 
prepared skins for tanning by the ordinary process ; 
he placed them in vats filled with stalks and skins of 
grapes (previously distilled to save the alcohol); he 
allowed them to remain from thirty-five to forty-five 
days, which time he found sufficient. The advantages 
of this process are the following : 1st. Less time is re- 
quired. 2d. A refuse material of some localities is sub- 
stituted for the expensive oak bark. 3d. The leather 
produced has a slightly agreeable odor. 4th. The leather 
obtained by this process lasts twice as long as that ob- 
tained by the ordinary process." 



358 TANNING. 



CHAPTER .LIX, 

TANNING WITH STATIOE {Marsh Rosemary). 

This process was discovered by Mr, Tournal, and we 
give below the full details, extracted from a paper written 
by him on the subject. 

Mr. Gayraud and himself commenced an experiment 
with an ox-hide, while another tanner, M. Mallaret, 
undertook to prepare some goat-skins. Mr. Gayraud 
prepared the hide in the same manner as with the bark 
of the root of the kermes-oak, except that he divided it 
into two equal portions; one he tanned with the statice 
and the other with the root of the kermes-oak, in order 
to determine what difference in weight would be produced 
by the two materials. 

Six months had passed when the heat of the weather 
produced, in the statice liquid, so active a fermentation 
that it burst the vessel containing it, so the experiment 
could be carried no further. The tannin had penetrated 
nearly to the centre, and probably two months more of 
exposure would have completed the process. The leather, 
examined by good judges, was declared of the very best 
quality. Mr. Mallaret declared that goat-skins tanned 
by this process were superior to that with oak bark. 

M. Tournal, in one year, tanned perfectly a piece of 
thick Buenos Ayres hide, which in the ordinary wfty 
would have required eighteen months. 

M. Gayraud then commenced the tanning of more 
than 100 horse-hides and 50 imported cow-hides, while 
M. Mallaret tried 150 goat-skins, and M. J. Galas, 80 



TANNING WITH STATICE. 359 

horse-hides, the cow-skins being intended for soles, the 
horse-hides and goat-skins for upper leather. 

M. Gayraud placed the cow-skins in the lime pit, to 
depilate and rise them. The lime revealed many de- 
fects and injuries, so that out of the fifty hides, one-third 
were piore or less damaged, and some had to be trimmed 
to one-half their size in consequence of being injured. 
This prevented ascertaining the difference in weights in 
the process, but it was found that the hides were tanned 
in a third less than the usual time. They were remark- 
able for weight, beauty, color, and strength. The same 
operator weighed exactly a certain number of perfect 
skins ; he tanned them by the statice, and obtained the 
mos^t satisfactory results. 

In the preparation of horse-hides, the superiority of 
statice as tan was evident in the finer structure of the 
product, shortness of the process, economy of material, 
beauty of color, increased weight, power of absorbing 
fatty bodies, etc. The same advantages we^g perceived 
in goat leather. 

All the skins thus prepared have been sold, and work- 
men who used them preferred them to those tanned 
by the usual process. They equal skins tanned with 
kermes-oak bark for wear in damp weather, while in dry 
weather they are much superior. As to flexibility, they 
hold thread better, and are more easily worked. The 
leather for uppers is remarkable for suppleness and firm- 
ness, and for the brilliancy, intensity, and durability of 
the black color which can be given to it. 



360 TANNING. 



CHAPTER LX. 

LEPEIEUR'S TANNING PROCESS. 

Four operations, about similar to those followed by 
tanners, constitute Leprieur's process. 

1 . The rinsing, comprising the softening of dry hides, 
washing, swelling, etc. 

2. The sugar of lead hath. 

3. The tan liquor hath. 

4. Tanning. 

A. SUGAR OF LEAD BATH. 

This operation comprises the following manipulation : 
1st, the hides being well washed and drained are put 
into the bath ten to twelve hours in summer, and 24 to 
30 in winter. This bath is thus prepared : — 

Acetate of lead (sugar of lead) . . 1 lb. 
Water 125 gals. 

Such a bath is sufficient for 6 to 8 hides. 

It is to the precipitate formed by this salt and the 
albumen that the author attributes the solidity of the 
leather, which is neither hollow nor brittle.. When out 
of this bath put it in another prepared in the same pro- 
portions, being careful in the two immersions to stir the 
hides every three or four hours. After remaining 12 
to 24 hours in this bath, wash carefully in running 
water. 

B. TAN LIQUOR BATHS. 

The author contends that the raising is not an essen- 
tial condition for tanning, and if necessary it can be 



leprieur's tanning process. 361 

obtained by adding acid in the first infusions ; he gives 
the proportion of 1 part of tan for 10 parts of dry hides, 
with enough sulphuric acid to impart a decided acid 
taste, as being all-sufficient for the purpose. 

First Series of Infusions. 

First Bath. — This bath for every 110 lbs. of hides is 
composed of 22 lbs. of tan ; infuse the hides for 24 hours 
in enough water to cover, but not completely sink them. 
To this mixture add from 9i to 91 ounces of sulphuric 
acid at 66° B. If after a maceration of 24 hours the 
liquid is not sensibly acid, add some more, if it is desired 
to raise by it. 

In summer keep the hides in this bath 30 or 40 hours, 
for after that time it will putrefy. In winter they may 
remain one day longer. 

Second Bath. — For 110 lbs. of hides use 33 lbs. of tan 
and ricidify this bath as the above. Keep the skins in 
for 36 hours, take them out to drain, immerse them 30 
hours more, and drain again. This bath is no longer 
serviceable except as a putrid ferment for new infusions. 

Third Bath. — For 110 lbs. of skins use 44 lbs. of tan, 
and add 9i ounces of sulphuric acid, if the previous 
raising has been considered sufficient. Take out the 
skins by intervals, wash in water, drain and replace. If 
after a stay in the bath of four or five days it shows 3° 
or 4° by the acid hydrometer, allow the skins to remain 
24 hours longer, or better, the liquid may be used in the 
same manner as the first bath for thin skins. 

Fourth Bath. — Operate as above, using 55 lbs. of tan, 
and leaving the skins in it for six or eight days. The 
skins before being placed in the vat are drained for eight 
or twelve hours, and are taken out at least three times 
to ascertain that the liquor has not become too weak. 



362 TANNING. 

If the degree shown by the acid hj-drometer is four or five 
tenths, prepare a fresh liquid and reserve the old one for 
skins which are undergoing the second series of baths. 
According to Leprieur, it is better to deposit fresh skins 
in old baths which they quickly exhaust, than in those 
more advanced. 

s 

Second Series of Infusions. 

First Bath. — According to Leprieur a new set of skins 
begins with the fourth bath of the first series of infusions, 
and require 330 lbs. of bark to tan them as completely 
as the others. 

Second Bath. — Since the fifth bath of the first series 
would not be disposed of in time to answer for the second 
bath of the second series, and would moreover be too 
strong, a new one should be prepared like that of No. 
2. After the fourth bath stratify the leather and tan, 
alternately interposing willow twigs so that the surfaces 
be equally soaked. 

First Series. — Fifth Bath. — For 110 lbs. of hides use 
66 lbs. of tan. Keep the hides in the vats 6 to 8 days, 
take out, draw, and replace three or four times during 
this period. If strips of wood are placed between them, 
it will be sufficient to cover the last layer of tan with the 
infusion to the height of I an inch. 

Second Series. — Third Bath. — The fifth bath forms the 
third of the second series. 

Siocth Bath. — To 110 lbs. of hides use 66 lbs. of tan, 
leave 10 days, take out and drain at intervals of two or 
three days. When the infusion marks more than 5 or 
6 of the acid hydrometer, take the skins out, and the 
bath is reserved for others which are less advanced in 
preparation. 

Fourth Bath. — The fifth bath like the sixth, not being 



leprieur's tanning process. 363 

unoccupied soon enough to answer for the fourth of the 
second series, it is necessary to prepare it with fresh 
materials, hke No. 4. It is then the sixth of the first 
series under the denomination five. 

Fifth Bath. — The hides can remain in this bath until 
the fifth bath of the first series is fully prepared ; there 
is then no more danger of the putrefaction of the hides. 

Seventh Bath. — For 110 lbs. of hide use 88 lbs. of 
bark. Leave the hides to remain twelve or fifteen days, 
or until the liquid marks no more than from six to seven 
by the hydrometer. After that time it will serve for 
the second set of skins. When the hides are taken from 
this bath and cut, the section shows a well-tanned sur- 
face, while the inside is unchanged. The operation has 
taken nearly fifty days, and every 110 lbs. of hides have 
consumed 385 lbs. of bark. Supposing that 1100 lbs. 
of tan are used to tan that weight of leather by the 
ordinary method, there still remain 717 lbs. to be used in 
the pits to make the expenditure the same. 

Sixth Bath. — The seventh bath of the first series is 
the sixth of the second; but it is a matter of indifference 
whether the hides are at once deposited in the vats, or 
again exposed to a bath of 110 lbs. of tan to an equal 
weight of leather. 

C. TANNING IN THE VATS. 

Leprieur uses tan well mixed with water, to which 
he adds sulphuric acid in the same proportions as above 
indicated. Upon the bottom of the vat he deposits a 
layer of this mixture ; he spreads a hide upon it, and 
he continues the stratification until the vat is filled. 
The last hide is covered with a stratum of one inch of 
the mixture ; he throws in a quantity of water sufficient 
to rise above the surface, and covers the whole with 



364 TANNING. 

weighted boards to prevent the skins from floating. The 
liquid of the vat is tested every three or four days with 
the hydrometer, to ascertain if any diminution of strength 
has taken place. In this case the skins are taken out, 
and deposited in another vat. Taking into consideration 
that 110 lbs. of good tan give 1320 lbs. of infusion 
marking 1° of strength by the hydrometer, and 10° or 
12° of the acid hydrometer after forty-eight hours, it 
will be easy to ascertain, day by day, from the diminu- 
tion of density, how much of the tanning principle has 
been absorbed. When the infusion has lost one-half of 
its strength it will still serve for other processes, and 
another supply of tan is given. 

First Tanning in Vats. 

For the first vat use one hundred parts of tan for one 
hundred parts of hides, the water being mixed as before 
with a little more than nine ounces of sulphuric acid. 
Leave the skins in this first vat, twelve to fifteen days, 
and besides testing the liquor by the hydrometer, the 
skins should be cut from time to time, to ascertain the 
progress of the tanning. If considerably advanced, and 
if the liquid is reduced to five or six-tenths, the vat 
should be changed. 

Second Series. — The contents of the first vat are not 
exhausted, but furnish a strong infusion for a sixth bath 
for the second set of skins. 

Second Tanning in the Vat. 

Expose 100 parts of skins with 120 parts of tan, for 
fifteen days. 

First Tanning. — The preceding or second tanning of 
the first series forms the first tanning of the second 
series. The skins taken from the first tanning are then 
exposed to the second. 



leprieur's tanning process. 365 

Third Tanning. — Expose 100 parts of hides with 130 
parts of bark, from fifteen to twenty days ; the prepa- 
ration is the same as before. Examine carefully the 
hides, as probably the thinnest ones are tanned. 

Fourili Tanning. — This is the second of the second 
series. Use 140 parts of tan for 100 of hides; expose 
from fifteen to twenty days. -r 

Third Tanning. — The preceding, or the fourth of the 
first series, serves as the third of the second series. 

Fifth Tanning. — Use 160 parts of tan for 100 parts 
of hides; expose from twenty to thirty days. This 
quantity of 176 lbs. completing the 1100 lbs., used for 
the first series. 

Fourth Tanning. — This is the fifth of the first series. 

If after twenty days the tanning is not completed, 
from fifteen to twenty days more may be allowed to 
elapse before the leather is taken out; this being the last 
tanning. 

• If it should be necessary to add 220 lbs. more of tan 
to the amount already used, 220 lbs. of leather would 
be completely tanned by means of 1650 lbs. of bark. 

Quantities of Tan Employed for Tanning 220 lbs. of 
Leather. 



First Series. 



Tan for baths 
" " pits 

Tan for baths 
" " pits 



385) 
716) 



Second Series. 

. 88") 



1101 



264 



1365 



Accordins; to the author :- 



366 TANNING. 

Strong and supple Jiides are tamied in from 100 to 130 

days. 

Middling ones in about 150 days. 

Refractory ones in about 180 days. 

Sometimes a sixth tanning is required, which does not 
much increase the duration or expense of the prepa- 
ration. *► 



CHAPTER LXI. 

D'AECET'S PROCESS BY THE SULPHATE OF SESQUI-OXIDE 

OF IRON. 

According to this author, this process is simple and 
economical, the time of working it short, the price of 
the material very low, and it seems at first that this 
process is to be preferred to any other. 

A solution of sulphate of peroxide of iron poured in 
a solution of gelatine or albumen produced an abundant 
precipitate similar to that obtained with tannin ; thus a 
skin dipped in a solution of sulphate of sesqui-oxide of 
iron can be perfectly tanned. It had some inconveni- 
ences : it is that some free sulphuric acid was left free in 
the leather, and the other was that salts of iron disor- 
ganize the leather. Boucherie has seen that by intro- 
ducing linseed oil, this last inconvenience was removed. 
The destructive action of sulphuric acid can be avoided, 
as we have seen, by dipping the leather in a weak solu- 
tion of soap. This process is very short; four days are 
suflQcient for thin skins and eight days for thick ones. 
We have no doubt this is an advantageous process, and 
before rejecting it we must wait for the results of the 
experiment on a large scale. 



Newton's process. 367 



CHAPTER LXII. 

NEWTON'S PROCESS. 

This method is an accelerating process combining 
the use of mineral and vegetable substances. It con- 
sists in the employment of certain earthy alkaline or 
metallic salts for the preliminary treatment and of 
an astringent for the tanning. This joint action pro- 
motes the combination of the albuminous matter of the 
skin with the bases. When other material than catechu 
is used, the latter of good quality and containing 50 
per cent, of tannin is taken as standard for regulating 
the proportion of the former. The skins must be un- 
haired and free from lime. 

FOR 100 CALF-SKINS. 

Take: 

Alum .20 lbs. 

Salt 10 " 

Catechu 100 " 

Sulphate of alumina 4 " 

This latter can b^ used either alone or mixed with 
2 lbs. of common salt. The three mixtures are dissolved 
in water and kept apart in separate vessels. 

In a vat place ^ of the first solution, J^ of the second, 
and I of the third ; immerse the skins in this liquor, 
handle and stir them repeatedly for a short time, then 
take them out. Then refresh the vat by the addition 
of ^ of the first solution, J^^ of the second, and I of the 
third. Replace the skins in this mixture, treat as 
before, but a longer time. Remove the skins a second 



368 TANNING. 

time, refresh the vat with i of the first solution, -^^ of 
the second, reimmerse as above. Let them remain some 
time, handle occasionallj, remove again, and mix in the 
vat the residues of the first and third solutions and ^ 
of the second. Put back the skins, a few days after, take 
them out to add to the vat the remaining f of the se- 
cond mixture; four or five weeks are sufficient to complete 
the tanning. 

This process may be modified by laying the skins in 
a vat and stratifying them with 3 lbs. of moistened tan. 
Other skins can be thus tanned, but the proportions vary 
as we could see below. 

One hundr.ed goatskins require — 

Alum 10 to 12 lbs. 

Catechu 50 to 60 " 

Salt 6 

One hundred cow-hides require — 

Sulphate of alumina . . . . 2 to 300 lbs. 

Salt 100 

Catechu 500 " 

One hundred and ninety ox-hides require — 

Sulphate of alumina .... 14 to 16 lbs. 

Salt 8 

Catechu 60 to tO " ' 



CHAPTER LXIII. 

PEEPAEING DEY FLINT HIDES. 

As a green hide becomes dry by evaporation of its 
liquid, the flesh side absorbs oxygen from the atmosphere 
which, combining with the fresh fibro-gelatinous surface, 
forms a hard, flinty scale. To free the hide from the 



PREPARING DRY FLINT HIDES. 369 

scale and facilitate its softening, tanners submit it to 
hard beam breaking, or to the action of a hide-mill, both 
of which have the detrimental effect to some extent of 
disturbing the uniform relations of the interposed gela- 
tine and loosening the small bundles of fibres composing 
the structure of the hide, thereby weakening the hide 
in its textile strength, nor have any of the modern soaks 
proved less detrimental, depending as they do upon a 
putrefactive condition. The first effect of such soak is 
to decompose the parts of the hides easiest affected, gen- 
erally the fibro-gelatinous structure, immediately beneath 
the scale; hence the frequent water peltings and running 
of hides in the soak, particularly in warm weather. 
M, Aldrich, of St. Loui.s, Mo., to obviate those objections 
and at the same time render the hide soft and pliant, as 
when first taken from the animal, has invented a chemi- 
cal process for preparing dry flint hides, and accomplishes 
it in the following manner :— - 

First. The hides are soaked in clear water until 
limber, then placed in the following acid bath — 

Acetic acid ........ 1 

Water 16 

which will in from 24 to 36 hours dissolve the scale by 
combining with its oxygen or swell the fibres of the 
hide ; when they are placed in the following bath — 

Water . .70 

Carbonate of ammonia . . . . . . 1 

which having a strong affinity for the acid absorbed in 
the first bath, saturates in from 48 to 72 hours all the 
acid remaining in the hide, leaving a hide in a naturally 
pliant and soft condition, so perfectly transformed from 
a dry to a green condition, that no tanner can detect 
24 



370 TANNING. 

ihe slightest difference between stock tanned from dry 
hides so prepared or from green hides. 

The first cost of the acid solutions is two cents a 
gallon, or $20 for a large poolful, after which it can be 
used continually, attended with no expense except pump- 
ing up and passing it through the apparatus to renew 
its strength after it has been used. 

The second solution is prepared from all bate water 
attended by no expense but pumping. 

This process obviates all danger of damage from taint 
or running, for its action is so perfectly antiseptic that 
hides so softened may be kept for weeks in water before 
being placed in the lime, also by keeping fibrous and 
flanky hides in the first bath, double the ordinary time, 
they will plump up and be materially improved and all 
without any breaking whatever. Hereafter we will 
treat of the full process of tanning of the same inventor. 



CHAPTER LXiy. 

PROCESS OF TANNING OF H. 0. JENNINGS. 

A SHORT process of treating hides, with the use of very 
little tan bark, to make leather has been patented by H. 
C. Jennings, London. In the preparation of thick ox- 
hides by this process, the hair is first removed in the 
usual manner, either by steeping them in a lime bath, as 
in the old mode, or by sweating, according to the new 
methods. If lime is used, the hides are steeped in dilute 
muriatic acid after they are unhaired and washed. 
This opens their pores and fits them for the succeeding 
operations; they are now piled in batches of a dozen 
hides in each, with a hurdle or wicker between each 



BERENGER AND STERLINGUE'S PROCESS. 371 

pair ; and they are then alternately lowered into tanks 
filled with the following solution : — 

Tank No. 1 is charged with a strong solution of alum, 
to which ten per cent, each of sulphuric and muriatic 
acids are added. 

Tank No. 2 is charged with a concentrated solution of 
soda ash, to which is added five per cent, of tungstate 
of soda. 

The skins or hides are immersed six hours at a time 
in these tanks, then withdrawn and drained, and trans- 
ferred alternately from the first to the second, and vice 
versa, until the hide is sufficiently hardened. This con- 
dition of the hide is known by cutting a small piece oiF 
with a knife. At this stage they are immersed for six 
hours in a strong solution of tungstate of soda alone, then 
lifted, drained, and placed in a liquor of soap made by 
dissolving twenty pounds of soap in every ten gallons of 
water, and the hides agitated in this until the strength 
of the soap is exhausted by being absorbed in the hides. 
Wash them well in soft water, and finally steep them 
for 24 hours in a common liquor of oak bark, after which 
they are dried and finished in the usual manner. This 
process is too costly. 



CHAPTER LXV. 

BERENGER AND STERLINGUE'S PROCESS. 

In 1842 Messrs. Berenger and Sterlingue patented 
the process described below. Their method reduces the 
time occupied in tanning, within the reasonable limits of 
from four to five months ; thus avoiding the extreme of 
allowing too short a duration for a process which, to be 
successful, must be more or less gradual or prolonged. 



372 TANNING. 

When skins are deposited in vats with water and 
layers of tan the infusion marks generally 25° of the 
hydrometer. As the combination progresses the strength 
diminishes, and after four months it generally marks 4°. 
At this time the skins are transposed in fresh vats, and 
this change is repeated a third, and often a fourth time, at 
every interval of four months; each time the hydrometer 
sinks from 25° to about 15°, 12°, 10°. The introduction of 
tannin into the skin becomes more and more slow, owing 
to the obstacles to the penetration into the tanned surfaces. 
The object of these manufacturers was to find means of 
tanning which keep the skins in contact with infusions 
gradually increasing instead of diminishing. For this 
purpose they placed in the vat a wooden cylinder through 
which the infusion could be removed by pumps, and re- 
placed by fresh and stronger liquor when necessary. 
Thus, they succeeded in tanning in a comparatively 
short time and avoiding the renewal of the contents. 

To moisten a freshly filled pit requires eighty tubs of 
water ; the tan absorbs the largest portion, leaving about 
only ten tubs of infusion, which can be pumped without 
injuring the hides and altering their relative positions. 
Messrs. Berenger and Sterlingue avoided this difficulty by 
removing the old infusion from the pits at the same time 
that it was exactly replaced by the introduction of fresh 
and stronger liquids ; but their mode was irregular, and 
it was necessary to devise better means to attain their 
objects. 

They provided a row of vats with wooden cylinders 
which were connected above at a depth of six inches 
below the surface of the pits by means of a pipe passing 
from one to another, which communicated below by 
means of a perforated tube with an open space under a 
false bottom in the pit. By this arrangement it was only 



BERENGER AND STERLINGUE'S PROCESS. 373 

necessary to open a stop-cock and admitting fresh liquor 
into the weakest pit to enable the fluid, which had no 
other means of escape, when this was filled, to traverse 
the entire range of pits, filling each one from the weakest 
to the strongest in succession before it was possible for 
any of it to enter the next one. 

Let us suppose a series of eight pits thus arranged, 
each provided with its cylinder opening by a perforated 
tube into the false bottom, and connecting with the cyl- 
inder of the next pit at a depth of six inches below the 
surface. Stratify the hides with the tan, in the end of the 
pit, pour water into it in the ordinary way. Leave from 
fifteen to twenty-one days, then fill a second pit with 
dry tan and skins, and since eighty tubs of water were 
required for the saturation of the first one, the same 
quantity properly graduated is poured into the first pit; 
this liquid, on descending, takes the place of that origi- 
nally contained into it, then it has no other means of 
escape than to pass out in the second pit in quantities 
exactly proportioned to those which enter the first one. 
Fifteen or twenty days after repeat that operation, a 
stronger infusion being introduced into the first pit for 
the purpose of filling the third one with the contents of 
the second, and the second with those of the first. Con- 
tinue the same way and at the same intervals until the 
eighth or last pit is filled. Close the communicating 
pipe, pump the infusion from the first pit, take out the 
leather to dry ; deposit in the pit fresh hides and tan ; 
this pit now becomes the eighth pit of the series. The 
second becomes the first, and is supplied with eighty 
tubs of strong infusion. 

We see that one application of tan is alone required ; 
the pits are not changed until the leather is removed, 



374 TANNING. 

securing thus a great economy of time and laljfor. It 
generally lasts from four to six months. 

An exposure of six months in eight pits is sufficient, if 
the strong infusion is added every fifteen days ; if the 
operation seems to progress too rapidly, lengthen the inter- 
val to three or four weeks ; in this case the process requires 
from six to eight months. The number of pits could be 
increased or diminished. 

The infusion for watering the pits is prepared in the 
following manner: — 

As the leather is taken out to dry, the infusion is 
transferred to a set of vats which are provided for the 
purpose, and which are like those used to furnish the 
liquor for a tan bath. Lixiviate these infusions as we 
have described, and mix with them some fresh tan to 
give the requisite strength. If the liquid is only at 30° 
and is required to be at 60°, place it in a large reservoir 
which connects with a trough. This trough, by means 
of a pipe, communicates with a second, a third, and a 
fourth below each other. All have pipes running longi- 
tudinally along their bottoms. 

Pass steam along these tubes so as to heat the infusion 
which passes successively from one trough to another, and 
to concentrate it to any desired point, so as to increase 
its strength and deprive it of the fatty matter and gallic 
acid which it may have absorbed during its passage 
through the pits. Let it off by a stop-cock into a 
reservoir below where it cools, then pour it into the pits. 

This system is applied to a bath of tan liquor. How- 
ever, the skins are not daily transferred from the vat 
containing the weaker liquor to that of the stronger, as 
in the ordinary method, but are placed upon horizon- 
tal shelves adapted to each vat and are not taken out 
until ready for the tan-yard, the liquor being passed from 



BERENGER AND STERLINGUE'S PROCESS. 



375 



vat to vat as in the pits. It may replace the old system 
of tanning the skins by floating them in tan and water. 
In that process, the skins, tan, and infusion are all thrown 
into the vats; after a certain time, the skins are taken out, 
the infusion is drained off and replaced in the vat with 
the same skins and fresh barks, the change being fre- 
quently repeated until the tanning is complete. By this 
new method, these removals are unnecessary ; it is suffi- 
cient to introduce fresh liquor into the oldest vat and 
keep it constantly full; so that the others will be filled 
in succession. The tanning by this process is more com- 
plete, regular, rapid, and economical ; it saves much 
labor necessary in the other process. 

The following is a description of the different appa- 
ratus : — 

Fiff. 15. 




Figs. 75 and 76. Apparatus, for giving the baths to 
hides-; 1, 2, 3, 4, 5, 6, 7, square vats, forming a series. 



Fig. 16. 




i 



376 



TANNING. 



a. Skins A, placed from head to tail, across horizontal 
crosspieces f, and resting upon them without touching 
each other. 

h. Exhibits the bottom of the pit, with the false bot- 
tom taken out ; and c shows the latter in place. 

d. Tubes in the bottoms of the pits, pierced with holes 
to receive the infusion. Their vertical parts, e, are not 
pierced, but conduct the fluid upwards from, the bottom 
of one vat to the top of the next one. Their upper ex- 
tremities turn horizontally into the adjoining pits, so that 
they cannot communicate excepting through these 
tubes. 

g. Horizontal tube, connecting vat No. 7 with No. 1. 
As all the vats communicate, fluid poured into one 
readily passes through all. 

I. Cock, to prevent connection between Nos. 1 and 7, 
when it is not desired. 

h. False bottom. 

?. Arrows, indicating the direction of the motion of 
infusion from 7 to 6, etc. 

Figs. 77 and 78. Series of pits. 1, 2, 3, 4, 5, 6, pits, 



forming a series. 



Fiff. 77. 




a. Skins deposited in pits, alternating with beds of 
tan. 



BERENGER AND STERLINGUE S PROCESS. 



377 



h. View, or plan of pits, with the false bottoms re- 
movecf, and showing d, tubes curved and pierced with 

Fig. tS. 




holes in this part alone : the vertical portion of the 
tube passing up and turning over under the surface, into 
the next pit. 

c. Plan of pits with the false bottoms in place, above 
the tubes. 

i. Arrow, showing the movement of fluid from one 
pit to another. 

h. Bungs, or stoppers, used when necessary, to pre- 
vent the passage of fluid. 

I. False bottoms, cullendered. 

Fig. T9. 




378 



TANNING. 



Figs. 79 and 80. Apparatus for regenerating old tan- 
liquor, and concentrating it to the desired strength. 

Fig. 80. 




=©=3/" 



a, h, c, d. Troughs placed one above the other, so that 
the infusion in a runs down into h, into c, and into d, 
through the tubes k, k', k", h'", with the stopcocks o, o', 
o", o"\ 

At the bottom of each trough is a serpentine tube w, 
extending over the whole surface, as seen in the plan. 
The vapor enters each tube upon opening the stopcocks 
s, s', 6-", s'", in the tube I. 

e. Reservoir, in which the liquor to be purified is first 
placed. It escapes from this through the tube g, into 
the first trough. When this is full, the fluid still run- 
ning from the reservoir, the cock o is opened, a«d the 
warm and already partly concentrated fluid runs into 
reservoir h, and so on successively, until the concentrated 
liquor passes through the cock o"" into a trough in which 
it is allowed to cool. 

/. Escape-pipe, conducting the condensed water and 
waste vapor into the open air. 

jp. Pipe, for the entrance of steam. 

The drawings represent only six and seven elements 
of the series of pits and vats, while reference has been 
had in the text to eight. 



corniguet's process. 379 



CHAPTER LXVI. 

CORNIGUET'S PROCESS OF SUBSTITUTING THE FRUIT OF 
THE PINE FOR TUB BARK IN TANNING, 

Put the skins in the lime, draw them once every day, 
and keep them till they depilate easily. 

Wash them carefully. Put them into the vats. For 
100 calf-skins, weighing from 400 to 500 lbs., are re- 
quired 200 lbs. of powdered fruit, which is introduced 
into the vat in five hours at the rate of 40 lbs. every hour. 
Stir them for six hours, raise every day, change them 
every eight days in summer, and fifteen in winter, let 
them drain two hours above the vat. 

Put them back in half of the water used in the pre- 
ceding operation, and then withdraw the first powder, 
spread them one by one, covering them with fresh 
powder«so as to use 300 lbs. Leave them six weeks in 
summer and three months in winter, raise, wash, and 
drain them 24 hours. , 

Lay them in dry vats, putting alternately a laj-er of 
powder, and a layer of skin, putting more powder on the 
thickest parts ; leave three months and they are readj^ 

The fruit of the ordinary pine tree, and the larch tree 
reduced into powder, can be thus substituted fur oak- 
bark, but that of the larch tree is better as containing 
more tannin. 



380 TANNING. 



CHAPTER LXVII. 

VAUQUELIN'S PROCESS. 

The means employed by Vauquelin to perfect the 
process of tanning rest on different principles, and we 
have combined them so as to make the four following 
effects clear : — 

1st. Not to alter the skins by a chemical reaction. 

2d. Prepare the hides, by mechanical means, so as to 
render them more apt to receive the tanning matter. 

3d. Shorten the work. 

4th. Handling in tallow, and dressing the hides by 
mechanical means. 

The first operation consists in preparing the hides for 
tanning by soaking them while fresh for a few hours, 
then submitting them to the action of the machine de- 
scribed hereafter. When the hides are dried they are 
treated in the following manner : Soak them some time, 
about forty-eight hours. Place them in a fulling machine, 
in which they are submitted to the action of wooden pestles 
for about one hour. The blows soften the hides and 
render them fit to be cleaned. 

In that state they are placed in another apparatus, 
in which they are treated for some time by introducing 
steam into the apparatus, so as to raise the temperature 
to 104 or 122.° From there the hides are carried in 
another vessel or oven, in which they at-e submitted to 
the action of tepid water which penetrates and humects 
them for twenty-four hours. The temperature must be 
uniform, for if the operation is conducted better on one 



vauquelin's process. 381 

place than on another, you run the chance of producing 
a hollow skin, and diminish its quality. 

When you operate on small quantities at a time, this 
operation is sufficient to depilate, but on large quantities 
it is important to act quicker. In this last case weak 
lime-water is used instead of a milk of lime, and the tem- 
perature is regulated according to the number of skins 
operated upon. 

When these operations are complete the hair is taken 
off easily. These skins are then submitted to the fleshing 
with the help of machinery. The machine, put in mo- 
tion by a man, acts on the hides, takes off all the fleshy 
parts which adhere to it, and prepares them for the 
subsequent operations. The advantages of this prepa- 
ration are, to submit to the tanning process only the 
parts really useful, while in the old method all the skin 
was tanned, and afterwards cut, thus causing a great 
loss. The parts of skins thus separated are used to 
manufacture glue. 

The hides thus treated are put into the fulling machine, 
and worked with tepid water for a certain time according 
to the nature of the hide. Then they are brought into 
the vat, where they are impregnated with a weak solu- 
tion of tanning liquor for a few hours, raised and piled 
up, and two hours after placed in a stronger liquor. 
The three first days raise them three times a day, and 
afterwards only once. Submit them to the action of the 
fulling machine every forty-eight hours, and put them 
back for half an hour in the same tanning liquor, where 
they are left until completely saturated. The action of 
the pestles of the machine opens the skins, and renders 
them more apt to receive the tanning substance, and by 
using the apparatus hereafter described, all the parts of 
the skin are put in contact with the liquor, which acts on 



382 TANNING. 

it rapidly and uniformly. At last, by tins process the ope- 
ration is executed much quicker than by the old process. 

The following is another method of operating: — 

The hides being placed in the vat, pass through it a 
current of steam, so as to raise the temperature to about 
104° or 116°. The skins by the rotative movement given 
to this vat are projected on its partitions, then Ml back 
on the bottom from whence they are successively retaken. 
This operation is continued for some time, till the hides 
are entirely deprived of hair. In that state they are 
placed in another apparatus to which a rotative move- 
ment is communicated. It is a drum to cleanse, which 
has in its inside a series of immovable pins, and which 
turn in a reservoir of water which raise to about half the , 
height of these pins. The hides in projecting on the pins 
are deprived of their hair by the rotative movement 
of the drum, and this hair falls to the bottom, and is 
carried away by the water, while a metallic grate pre- 
vents the hides going out from the drum. In that state 
the skins can be cut, and submitted to the operation 
above described. 

The following gives an idea of the manner of passing 
the skins through the tallow, and preparing them. 

After the skins are tanned by the above or any other 
process, cover all their surface with a fatty matter, 
composed of oil and tallow. These skins, thus greased, 
are placed in a cylinder, presenting on its inside surface 
a series of pins as we have explained above. Turn this 
cylinder, and the skins are projected on the pins during 
the rotation. This operation is continued for half an 
hour, after which time it will be found that the greasy 
matter has uniformly penetrated the skins, and that 
their surfaces present a dry aspect. Take them out, 
spread, dry, and prepare them as usual. 



VAUQUELIN S PROCESS. 



383 



This cylinder is not absolutely necessarj^ because this 
system of tanning prepares much better the skins des- 
tined to receive the greasy matters, but in many cases 
it is advantageous^ to use them. We now give a de- 
scription of the different apparatus which will cause this 
system to be better understood. 

Descriptio7i of the Figures. — Fig 81. This represents 

Fig. 81. 




the beating or fulling machine. A, B. Cog-wheels, giving 
motion to the shaft o, and to cams upon it, which alter- 
nately raise and lower the hammers e, e, e, to which the 
bar D serves as a guide. A movable trough for the skins 
is seen below, c, c. Cocks, which allow the liquid mat- 
ters contained in this trough to escape. H, h. Openings, 
through which the skins are introduced into the trough. 
I. Rack and pinion, by means of which the trough is 
moved to and fro, so as to bring all parts of the skins 
successively under the hammer. 

Fig. 82. Churning vat. This may consist of an open 
vessel, but a closed one will enable the operator to main- 
tain a more uniform temperature. A. Vat, closed by its 
lid. B. Shaft, carrying the cams or arms c, c. d, d. 
Tubes, through which cold and hot water, the tanning 
liquor, and steam are introduced, e. Ladder, by which 
the workman descends and regulates the cocks, f, f. 



384 



TANNING. 



Ground level, g, g. Water level in the vat. h. Door, 
which closes the opening in the vat. a. Toothed wheel, 



Fiff. 82. 




communicating its movement to the wheel 5, and the 
shaft. The arms of the shaft are straight, but may be 
made of various shapes. 

Figs. 83 and 84. These figures represent the machine^ 



Fig. 83. 



Fig. 84. 




for fleshing and paring the hides after they have been 
properly soaked and softened. 

It is composed of two cylinders, A and b, of copper, or 
other suitable metal, mounted upon a framework C, c, 
and forming a kind of cylindrical press. The upper one 
can be elevated or depressed by means of screws d, d, in 
the upper crosspiece of the frame, which act both upon 



vauquelin's process, 385 

the fixed supports h, h, and upon the sides of the frame. 
Upon this crosspiece, a shaft with a small fly-wheel i, 
works the endless screws f, f, which turn the cog-wheels 
E, E, by means of which the screws d, d. are turned in 
either direction. These screws carry, just below the 
wheel F, two shoulders or collars, upon w^hich the bar k 
is supported, and at the extremities of this bar, two de- 
scending cushions L are attached, which support the shaft 
of the cylinder A, and which are elevated or lowered by 
the bar, in accordance with the movement of the screw 
D. At the two extremities of the cylinders are cog-wheels 
of different diameters, m, n, m', N^ Those on the shaft 
of the lower cylinder b, are so attached to it, that it 
shares in their movement, while they ^re movable upon 
it, and can be slid to the right or left by two forks Q, Q, 
fastened to the bar v'", which passes across the frame- 
work. The wheels m, m', are geared with each other 
when the cylinders are a certain distance apart, and 
those at n, n', engage in turn, when the cylinders are 
brought in contact with each other, so that the cylinders 
turn simultaneously in either of these positions. At the 
extremities of the cylinders, there is a system of pulleys 
which communicate the motion to the machine by means 
of straps. 

Upon the interior and posterior faces of the machine, 
two knives, p, p', are fixed, which turn upon cushions 
supported by the pieces q, 5', seen on the frame. The 
knife p has a cutting-blade, which is retained in place 
and adjusted by means of screws, but the knife p' is dull. 

The skin, placed upon the upper cylinder, is drawn in, 
compressed, and stretched out in the direction of its 
length, between the two rollers. The wheels m, m', are 
then put in gear, and the knife p' is made to pass over 
the skin by pressing it against the upper roller by means 
25 



386 



TANNING. 



of a movable piece with two handles. The skin being 
now pressed between the rollers and gradually advancing 
through them, the cutting-blade, which is parallel to the 
surface of the cylinder, is put in action, and, like the 
ordinary fleshing-knife, it removes all the projections from 
the flesh side, and equalizes the thickness of the skin. 
Figs. 85, 86, and 87. These figures represent the re- 



Fig. 85. 



Fig. 86. 



Fig. St. 





volving cylinder or drum for depriving the skins of hair, 
which has already been partly described. 

A. Exterior of the drum; b, b, shaft of cylinder; c, 
cylinder; d, crossbars, forming the framework ; e, f, sepa- 
rate pieces of the set of crossbars ; G, G, internal surface 
of the Cylinder; h, wooden projections, fixed upon this 
surface ; i, metallic plate, closing the surface of the cylin- 
der ; L, door, closing the aperture ; m, m, tubes, through 
which water, tanning liquor, and steam are introduced 
into the cylinder; o, ladder, for the workman who attends 
to the stopcocks, to descend ; p, level of liquid in the 
cylinder ; h, 6, cog-wheels, communicating motion to the 
cylinder. 

Figs. 88, 89, and 90. These figures exhibit dijQferent 




Fig. 89. 



Fig. 90. 




vauquelin's process. 387 

means of keeping'the skins pressed upon the table when 
they are subjected to processes of paring by hand. 

a, a. Clamp or press for maintaining the skin in place ; 
b, b, the table ; c, c, a vertical bar sliding in a groove ; d, 
the lever which acts upon the press ; I, a catch which 
stops the lever d; f, weight at the end of the lever; g, 
another lever by means of which the press is raised, as 
has been before explained. 

Fig. 91 represents the press commonly used in this 
mode of preparing leather. 

The committee on chemical arts of 
the SocieU d' Micouragemetit, reported, in 
the Bulletin of the Society, most favor- 
ably upon the processes of Vauquelin. 
They believe that the expense of the 
various methods used by him does not exceed that of 
those ordinarily employed, while a great gain is secured 
by the rapidity of the process, and the smaller quantity 
of tan required by it. 

This process being described, we shall give the results 
of experiments made by the Societe d^ Encouragement, and 
reported in its Bulletins of 1841 and 1844. 

" African cow-hides, so dried by the sun that tanners 
thought them impossible to be tanned, have been chosen 
by Mr. Vauquelin to demonstrate the advantage of his 
process ; they have been marked and treated by the 
above process. To obtain all desired certainty in the 
quality of the leather, the committee invited the best 
leather dealers and manufacturers to assist in his re- 
searches. 

" After the skins had been tanned they were examined, 
and they were unanimously declared of good quality, all 
but one, that one of the judges declared incapable of 
being well curried. 



388 TANNING. 

" That skin was marked and all were curried, and all 
of them without exception were found perfect. 

"The leather could be smoothed and greased. By the 
first process the benefit would have been greater ; the 
second was more difiicult, and Mr. Vauquelin chose it to 
prove that skins tanned by his process present a peculiar 
character for currying— that of gaining in weight instead 
of losing. 

" One of the skins was converted into black leather 
which was of good quality , and it is a great advantage 
of this process to obtain skins apt to be used in different 
ways. 

" The following are the details of the operation : — 

23 skins weighing witli hair 77 K. (154 lbs.) weigh when curried 99 K (198 lbs.) 

1 Curried marked anew 3.500 (7 lbs.) " " 6 K (12 lbs.) 

1 Dry in crust 3.500 (7 lbs.) " " 4.500 (9 lbs.) 

3 For legs. 10. (20 lbs.) " " " 

1 For black leather. 5.500 (11 lbs.) " " 9.500 (191bs.) 

3 To smooth. 14. (28 lbs.) " " 21 (42 lbs.) 

1 For strong leather. 5.500 (11 lbs.) " " " « 

1 Bad and six fresh. 21.500 (43 lbs.) " " " " 



140.500 281 



" The work lasted two months, the currying had been 
put back on account of damp weather, and the difficulty 
of drying. 

" The quantity of tan used has been 1800 lbs., an 
inconsiderable proportion, but easily accounted for, if we 
remember that it is a quick process, and the transforma- 
tion of the tannin into gallic acid is less considerable 
than in the ordinary process." 

Later, in 1844, a new report gives the results of some 
new experiments. 

" 100 calf-skins weighing 360 lbs., three cow-hides 
weighing 14 lbs., and two horse-hides were put in experi- 
ment the 9th of January. 



vauquelin's process. 389 

" The eighteenth of March the calf-skins were tanned, 
the 4th of April the cow-hides were completed, and the 
horse-hides on the 12th of April. 

" One calf-skin was reserved for another experiment, 
the 99 others weighed 340 lbs., the three cow-hides 
18 lbs. 

"We see that calf-skins have been tanned in 68 days, 
cow in 85, and horse 87, while by the usual methods, it 
requires from 12 to 15 months. Col. Chompre, of the 
French Army, gives the following notes on the use of 
M. Vauquelin's leather. 

"1st. A piece of calf-skin forming a patch on a pair 
of trowsers, which were ridden in by a dragoon every 
day for eight months, was found at the end of that time 
in a perfect state, and as pliable as at first. 

"2d. A number of pairs of calf-skin boot-legs wore 
exceedingly well, preserving their firmness and pliability 
without any unusual care being used for their preserva- 
tion. 

"A pair of boots with ordinary tops, and with soles 
made of the tail part of the horse-hides, was worn by 
a non-commissioned ofiicer, who generally wears out a 
number of shoes. These are in good order, and have 
lasted, by his account, as long as two pairs of shoes. 

" Five other pairs of soles of shoes given to lancers, 
who wear out a great many in service, are in an excel- 
lent state of preservation. 

"3d. The blackened leather used for belts, girths, etc., 
has also worn well." 

The conclusions of the report of the administrative 
council of the regiment are — that the leather submitted 
to, and tried by them, was superior to any which had 
before come under their notice. 



390 TANNING. 



CHAPTER LXVIII. 

OGEEEAU'S PEOCESS. 

An eminent Parisian tanner, Mr. Ogereau, proposes to 
lessen the duration of the tanning process by a methodi- 
cal arrangement of materials. The skins are properly 
prepared by the ordinary method of separating the hair 
and raising; then he places alternate layers of tan and 
skins in a vat with a perforated false bottom. This vat 
being full to the f , is drenched with water for the first 
operation, and with weak tan liquor for the succeeding 
ones. The liquid penetrates slowly into the mass, and 
having moistened the contents, runs through the false 
bottom into a reservoir, from which it is carried back 
upon the surface of the materials. 

His arrangement consists of six vats,* each one 
contains 100 domestic or 120 imported hides. The 
liquid passing through into the reservoir is daily distri- 
buted over the surface by pumping. This operation is 
continued for one month, at the end of which time the 
vat is emptied and the spent bark replaced by fresh, 
and the same process is recommenced. A third exposure 
to fresh tan and repeated filtrations is necessary to obtain 
a proper tanning. This full process occupies four months, 
and the leather it furnishes is equal in quality to that 
obtained by the old method, one hundred parts of dry 
Buenos Ayres hides gives 150 parts of leather. 

* Dumas' Chimie Appliquee. 



TANNING WITH A DECOCTION OF OAK BARK. 391 



SECTION YII. 

AMERICAN, ENGLISH, AND OTHER PROCESSES. 
CHAPTER LXIX. 

PEOCESS OF TANNING WITH A DECOCTION OP OAK 

BAEK. 

The principle of this process is the same as that estab- 
lished by Seguin. Oak bark is boiled for four hours in a 
large copper kettle, and when the tan is exhausted the 
liquor is conducted by pipes into vats, where it is left to 
cool. Soak therein the hides, press them often, draw 
out and soak again. Place them from time to time in 
a fresh liquor, if the first is too weak before the operation 
is terminated ; by this method a larger quantity of tannin 
is concentrated in a given space, and the labor is less. 
If the leather is desired whiter, mix with the liquor a 
certain quantity of powdered bark. By this process the 
hides are tanned better, and ten or twelve days produce 
the same effect as nine or ten months by the usual me- 
thod. This is true, but the leather thus produced is not 
completely tanned. The great quantity of tannin which 
is present rapidly tans the two surfaces, then they refuse 
passage to the solution, and the inside remains in the 
state of skin. There were the same objections to 
Seguin's process. 

Besides oak bark, the inventor uses again oak shavings 
and sawdust, and the ordinary heath. It has been 
ascertained that the bark of nearly all trees with a heavy 



392 TANNING. 

wood, contains tannin. They recommend, also,' the use 
of buds, roots, and branches of oak. They obtain thus 
a decoction of tannin stronger than that of the bark of 
the trunk which contains a thick matter difficult to 
separate. 

It had been shown, as early as 1819, that the trunk, 
roots, middle parts, branches and leaves of the oak, 
contained tannin in sufficient quantity to be used suc- 
cessfully in tanning. These are reduced into shavings, 
or coarse powder, boiled and used in the following man- 
ner : — 

To tan calf-skins or other light skins, take 200 lbs. of 
the middle part of the tree, or shavings of oak branches, 
boil them in a copper kettle, containing 50 galls, of water, 
until it is reduced to 37 galls. Draw the liquor, pour on 
the residue 37 galls, of fresh water which by ebullition 
you reduce to 20 galls. Keep this liquor apart. It is 
used to immerse calf-skins, when they have been worked 
on the beam. Pass afterwards in the first solution. 

For ordinary hides, take 200 lbs. of the middling part 
of the tree or branches, 150 lbs. of coarse powder of oak, 
and 25 lbs. of root, that you boil in 63 galls, of water until 
reduced to 42 galls., draw the liquor, and on the residue 
pour 50 galls, of fresh water and boil until reduced 
to 25 galls. This liquor is used for the first opera- 
tion of the tanning. Pass them afterwards in the first 
decoction. When the hides have been submitted to these 
two operations, add to each solution some oak bark, as 
much as necessary to complete the tanning. This quan- 
tity varies according to the strength of the decoctions. 

This method seems to us very incomplete, and the 
authors do not even indicate the number of hides the 
above proportion will tan, nor the time they must re- 
main in the solution. 



buebidge's process. 393 



CHAPTER LXX. 

DESMOND'S PEOCESS. 

This process, like the preceding one, is a modification 
of Seguin's process. He recommends saturating the 
water with tanning principles by infusion of successive 
portions of oak bark, or any other tanning vegetable ; 
and when the bark is exhausted, he extracts what is left 
of gallic acid by fresh water. To this last liquor he adds 
j-q\-q in measure of sulphuric acid, and leaves the hide in 
till the hair is easily removed. When the swelling is 
necessary, he leaves the hide ten or twelve hours in 
water, acidulated with 0.05 part in measure of sulphuric 
acid, he washes anew and fleshes with the round knife. 
He then leaves the skins for a few hours in a weak solu- 
tion of tannin, afterwards several days in a stronger 
solution, which must be renewed as the strength becomes 
exhausted, till the skin is completely tanned. 



CHAPTER LXXI. 

J. BUEBIDGE'S PEOCESS WITH EXTEACT OF OAK BAEK 
AND OATBOHU. 

Mr. Burbidge prepares leather with the extract of oak 
bark. He says that in ten days he obtains this extract 
without any loss of tannin, which requires two or three 
months in the ordinary tanning process. He regulates the 
use of this extract with an hydrometer called barkometer; 
in three or four months the tanning of sole-leather is 
complete. The only precaution necessary to be taken, 



394 TANNING. 

is to begin with, a weak extract at 3°, and to increase 
successively the strength by changing the liquor three 
times a week, so as to carry it to 20°, being careful to 
use the strongest extract when the leather is nearly 
tanned. His process increases the weight of the leather. 
Tanners take one year to tan a hide weighing 80 lbs. 
when green, and it weighs only 40 lbs. when tanned. 
In three months Mr. Burbidge tans a similar hide which 
shows a weight of 48 lbs., which demonstrates that the 
excess of time employed is injurious to the leather. He 
does not use more oak bark than they do, that is to say, 
about four to five lbs. for every pound of leather. 

England using yearly 117,000 tons of oak bark, of 
which 100,000 are imported from Holland, Mr. Burbidge 
wishing to liberate his country from this kind of tribute, 
proposes to substitute for oak bark the terra japonica, 
which, according to Mr. J. Dauks, has ten times greater 
tanning properties than oak bark. According to the 
experiments of Sir H. Davy, the specific gravity of^cate- 
chu and oak bark are : : 8i : 1. Then catechu worth in 
England £33 the ton, then as it is equivalent to 8 J tons 
oak bark, which at £10 the ton makes £85. It is clear 
that there is a large saving. The previsions of Mr. Bur- 
bidge have been realized, for catechu is now extensively 
used. 



CHAPTER LXXII. 

KLEMAN'S PKOCESS. 



Oak bark, such as is used in tanning skins, is usually 
taken off while the tree is in sap. It is dried in order 
to preserve it, and it is introduced into the tanning pit 
at the samcftime as the skins, together with the requisite 
quantity of water. But it will be understood that the 



kleman's process. 395 

tanning property as well as the chemical composition of 
the bark must vary, according as the drying is quick or 
slow, and the greater or lesser period of time during 
which the bark is allowed to be exposed to dampness 
before the tanning begins. In most cases the bark un- 
dergoes a commencement of acetous fermentation, which 
is completed in the tanning vats. 

Mr. Kleman recommends the following mode of opera- 
tion, in order to utilize to the best advantage the tanning 
principle existing, whether in gall-nuts or in oak bark. 

The bark, while still fresh, should be reduced to small 
pieces and placed in a cask. Add sufficient water to 
cover the stuff", and close the cask hermetically, so as to 
prevent the action of the oxygen of the atmosphere. 
Leave the mixture undisturbed during a few weeks, in 
order that the principles soluble in water may become 
thoroughly dissolved, and dissolve the liquid to separate 
it from the bark. If this liquid is subjected to a gentle 
heat of 113 to 115°, it will enter into vinous fermenta- 
tion, and will then contain enough alcohol to mark 1 to 
2°. If a skin is placed in this solution, it will become 
very rapidly tanned, but it will be hard and horny, because 
the liquor is too" much concentrated. If on the contrary 
it be diluted with water, one part liquor and four parts 
water, excellent results will be obtained, skins thus 
tanned are more supple and the grain is closer than when 
they are tanned by the ordinary method. Moreover, by 
this new method, the same quantity of bark will produce 
more tanning matter. It is not advisable to boil bark 
in water, because boiling coagulates the albuminous 
matter which induces fermentation. The author has 
assured himself by experiments of his own, that bark 
which has only undergone vinous fermentation gives 
much better results than that which has been subjected 
to acetous fermentation. 



896 TANNING. 



CHAPTER LXXIII. 

SPILSBURY'S PROCESS BY PRESSURE. 

The hides are very carefully depilated and prepared. 
They have all the holes sewed up, so as to render them 
water-tight ; they are then stretched by means of clamps 
upon rectangular wooden frames. The frame is exactly 
overlaid by another similar frame, which is screwed down 
to confine the edges and make them water-tight. 

Another hide is stretched as before over the upper 
ledges of this second frame, and a third frame screwed 
upon it as above. The whole three are bolted together 
by means of clamps, so as to form a water-tight vat. 
The frames are then set upright, and the ooze allowed 
to flow into the space intervening between the two 
others through a pipe leading into it from a reservoir 
above. A hydrostatic pressure is thus maintained, and 
the liquid column forces the ooze through the hide by 
slow infiltration, and brings thus all parts in contact 
with the tannin. 

In the bottom of the vat is a stop-cock to allow the 
escape of the air as the ooze enters, and the exit of the 
spent liquor when the operation is done ; but it must be 
closed carefully when the vats are full of liquor and in 
operation. There is also a stop-cock in the pipe leading 
from the reservoir to the vat, to shut ojff communication 
when the operation is completed. 

Let off the exhausted liquor by the stop-cock, replace 
it by fresh, and when the skins are completely tanned 



spilsbury's process. 397 

take the frames apart, pare off the edges, and dress the 
leather as usual. 

This process is rapid, but the time varies according to 
the pressure, the strength of the solution, and the quan- 
tity of the skins. There is more or less loss on account 
of the clippings and sewing of the skins. This method 
has not been as successful as it was originally anticipated. 

Messrs. Drake and Chaplin have modified this process, 
Mr. Drake gives to the hides prepared as usual an in- 
cipient tanning by immersion in weak ooze. After the 
necessary handling, he takes them out and sews them 
together at the edges, grain side within, in pairs, so as to 
form water-tight bags, with small holes at the end for the 
admission of the tan liquor. By means of loops, he sus- 
pends the bags between two upright Wooden racks, to 
prevent bulging when full. The cold ooze is introduced 
by a funnel, and by keeping the bag distended, creates a 
pressure, which causes the liquid to infiltrate through 
the skin. 

The fluid passing through is received in a vessel be- 
neath, and returned to the sack. When the skin becomes 
firm and hard towards the close of the operation, the 
temperature of the room is raised from 68 to 149°, and 
is maintained till the skins begin to darken in places, 
and the liquid ceases to lose strength. Take them 
down, empty them of their contents, and prepare as 
usual. 

The elevation of temperature promotes the infiltration 
of the ooze. To prevent indentations, the position of 
the bags should be occasionally shifted. 

By this process a skin can be tanned in ten days; the 
appearance is very favorable ; but we can say nothing 
about the quality and durabihty. 



398 TANNING. * 

Mr. Chaplin lays the bags in an inclined position, and 
turns them frequently so as to equalize the tanning. 

One great objection to this process is, that the hides 
are not equally permeable — some portions imbibing the 
liquor more readily than others. The leather is weak- 
ened by the prolonged distension of the hides. 



CHAPTEE LXXIV. 

M. W. DEAKE'S PROCESS. 

M. W. Drake has modified Spilsbury's process. After 
the hides have received the usual preliminary operations 
in a weak liquor of tan, they receive a first tanning 
before being submitted to the cold infiltration. Then 
he places skins, as much as possible of the same size, 
and same form, and sews them with waxed thread so as 
to form a bag, solid enough to retain the solution of tan. 
Then he suspends these bags with the help of ropes, 
sewed to their sides with tapes. At the upper end of 
the bag is an aperture large enough to introduce a fun- 
nel, by the means of which the cold liquor is introduced 
until the bag is full. After a certain time, variable 
according to the quality of the skins, their exterior sur- 
face becomes moist, and drops begin to form below the 
bag. This liquid is received in a convenient vessel, and 
when a sufiicient quantity is collected, it is poured anew 
into the bag. When the hides become hard and firm, 
while all the parts are equally moist, raise the tempera- 
ture from 68 to 149°; maintain this temperature until 
all the skins have become hard and firm at all the 
points. When the skins begin to blacken in some parts 



rotch's quick process. 399 

and the liquor does not diminish in strength, the skins 
are tanned. Then empty the bag by cutting the sew- 
ing, and terminate the operation in the usual manner. 
By this process a skin can be tanned in ten days, while 
by the ordinary method it requires ten months. 



CHAPTER LXXV. 

EOTCH'S QUICK PKOCESS OF TANNING LEATHER. 

This process consists in causing tannin to penetrate 
the skins by moistening them with tan liquor upon one 
side, while the water which passes through the pores is 
made to evaporate upon the other by artificial heat. 
Thus the greater part of the tannin remains in the 
leather, and the strength of the liquid increases instead 
of diminishing. By this method leather can be tanned 
in ten days. 

The skins are limed in the usual manner, soaked, 
and handled in a weak tan liquor for raising and color- 
ing them. They are prepared and cleaned, carefully 
examined, and if any holes are found they are pieced 
and sewed. 

They work two skins at a time, and they stitch 
together at the edges those of equal size v/ith tarred 
thread J they suspend them by cords (Fig. 92) to the 
pegs s, s, s, s, which project from the bar {a). This 
bar is the top of a wooden rack a, h, c, and there is a 
similar rack on the other side of the bag of skins, so 
that the latter can be compressed in such a manner as 
to make it retain its shape when full of fluid ; between 
the two ranges of uprights, which are made to approach 
one another by screws e, e, an opening about an inch in 



400 



TANNING 



length is left on the upper part of the bag for the re- 
ception of the funnel, through which the tan liquor is 




poured in. The funnel may be conveniently placed in 
the neck or collar, seen in the figure alongside of the 
rack. 

The figure 93 represents a section of the side view 
of the rack, and s, s, the pegs upon the head of the 
rack, from which the bag of skins is suspended. The 
inner sides of the central bars comprising the rack are 
hollowed out in the form of arcs of a large circle, as seen 
below. The skins being thus suspended, pour the cold 
tan liquor into the bag until full. After a certain time, 
varying according to the thickness of the hide, the out- 
side becomes moist, and the water which filters through 
drops into the gutter A, and flows into a receptacle 
placed below its spout. This liquid, as soon as cold, is 
poured back into the bag to keep it full, and the supply 
of the fluid is kept constantly in proportion as it loses 
by evaporation. 



ROTCH S QUICK PROCESS. 



401 



Fiff. 94. 



CO 



^i^. 



When the surface of the skin becomes firm to the 
touch, and equally moist, the air of the room is gradually 
heated from 70 to 150°, and kept thus until the skins 
become firm and hard in every part, and assume a brown 
color, and until the strength of the liquid in the bags 
remains the same. The skins are then thoroughly tanned. 

Take them from the frame, empty them, dry and 
prepare them as usual. 

The position of the skins, during the process, Fig. 95. 
must be changed often, so that the bars of the 
frame may not press for too long a time upon 
the same parts. 

The time of tanning varies according to the 
thickness of the skin, their change of position, 
the strength of the liquor, the regulation of 
heat, etc. 

The annexed figure shows a section of the 
rack ; 5, h, lower part of the rack ; c, c, bars 
of the two racks placed so as not to be opposite 
to each other. 
26 



402 " TANNING. 



CHAPTER LXXVI. 

J. F. KNOWLIS'S PE0CES8. 

Knottlis's process is an improvement of the above. 
He suspends the hides in an air-tight vessel, of a capacity 
larger than their dimensions. He hangs the hides at 
regular intervals, and keeps them distended by means 
of weights attached to their lower ends. In the upper 
portion of the vat is an opening, with a movable cover 
for the entrance of the workman. In the side, and near 
the top, is a tube with a stopcock, and coupling screw 
for connecting with an air-pump, and in a corresponding 
position on the opposite side, is a similar tube for the 
admission of air to create external pressure as may be 
required. As soon as a vacuum is obtained, the con- 
tents of the vat are left in repose for 24 hours, after 
which the tanning liquor is drawn off, and the appara- 
tus allowed to remain empty for two or three hours to 
permit the entrance of the air. Repeat this operation 
several times till the hides are perfectly tanned. 

The ooze is renewed after each exhaustion of the 
vessel, and the first liquid should be weak, and as the 
operation proceeds, the strength is increased. 

This process really accelerates the absorption of tan- 
nin by the hides, and saves time and labor. But to all 
these processes we prefer the one described in the follow- 
ing chapter. 



TANNING APPARATUS OF D. ALDRICH. 



403 



CHAPTER LXXVI I. 

TANNING APPARATUS OF D. ALDRICH, OF ST. LOUIS, MO. 

Mr. Dennis Aldrich, of St. Louis, Mo., patented, in 
1860, the following apparatus, of which we shall give a 
full description, as we look upon it as a decided im- 
provement. 

Fig. 96 is the plan of a tan-yard, with its apparatus 



Fi>. 9G. 




constructed and arranged according to his invention, the 
vats and tanks having their covers removed to show the 
apparatus inside of them. 



404 



TANNING. 



Fig. 97 is* a vertical section of the apparatus in the 
plane indicated in Fig. 96. 

Fig. 97. 




Fig. 98, vertical section of the same in the plane indi- 
cated in Fig. 96. 

Fig. 98. 




Fig. 99, vertical section of one of the tan vats in the 
plane indicated in Fig. 96. 

Fig. 99. 




TANNING APPARATUS OF D. ALDRICH. 405 

Similar letters of reference indicate corresponding 
parts in the several figures. 

H H'. Tan vats. 

/. Handler. 

J. Tan leech. 

K. Bat vat. 

L L. Tan liquor vats. 

M. Bate leech. 

N. Bate tank. 

0. Lime tank. 

P. Lime leech. 

R. Pool. 

S. Lime vat. 

These tanks and vats are arranged in three rows, as 
shown in Fig. 96, for the convenience of making the 
several pipe connections. The said tanks and vats are 
all made of wood, calked and pitched inside to make 
them tight, of the usual or of any convenient horizontal 
area, and of about 6 feet deep, and every one is pro- 
vided with a movable lid, a, fitted into a deep rebate 
formed recess provided round the top of the tank, such 
recess being deep enough to allow the lid to be covered 
with water, and to enable its edges to be covered with 
suitable paste or cement, to prevent the entrance of air, 
when a partial vacuum is produced in the tank or vat 
as hereafter described ; A A are two pipes, which he 
calls liquor pipes, arranged one above the other between 
the middle and one of the outer rows of tanks and vats, 
and each one connecting with tan vats, H H\ and with 
tan liquor tanks, L L', with the handler, I, and tan leech, 
eT, by means of a number of small branch pipes, 5, 5, 
each fitted with a stop-cock, 1, by which either of the said 
tanks or vats may be shut off from the liquor pipes. 

The said branch-pipeS; 5, 5, do not terminate in the 



406 TANNING. 

walls of the tanks or vats, but enter upright pipes, 6, 6, 
which are arranged close to the interior of the said wall 
within the said tanks or vats, such pipes, 6, 6, being 
closed at their upper ends, but open at their lower ends, 
which are within about one inch of the bottom of the 
tanks or vats, and being furnished, just below where the 
branches 5, 5 connect with them, with three way-cocks 
2, 2', by which the said pipes are made to communicate 
either with the bottom or the upper part of their respec- 
tive vessels, h h' are two pipes, which he calls conduct 
pipes, arranged one above the other between the middle 
and the other outer row of tanks and vats, and each one 
connecting the pool R, lime vat S, lime leech P, lime 
tank 0, and bate vat K^ bate leech M, and bate tank 
N, by means of short branch-pipes 5, 5, which, like the 
branch-pipes of the liquor pipes A A, are furnished with 
stop-cocks 1, 1, and like these pipes terminate in upright 
pipes 6, 6, which are arranged within the tanks and vats, 
and provided with three way-cocks 2, 2, in all respects 
like the pipes 6, 6, first described. These pipes and 
cocks are all best shown in Fig, 98. 

E E' are two air-pipes arranged one between the mid- 
dle, and each of the other rows of tanks and vats, above 
the liquor-pipe, and conduct pipes with branches 9 9 
connecting the two tan liquor tanks L L', the bate tank 
N, and lime tank with the air-tank X. These bran- 
ches 9 9 communicate with the tanks and vats near the 
tops thereof, and each of those connecting the air-pipe 
with the air-tank, is furnished with a stopcock 8, and 
each of the others with a stopcock 7. 

The air-tank X, which must be a perfectly air-tight 
vessel, has connected with it an air-pump W, by which 
to extract it, said pump being worked by hand or by 
steam. 



TANNING APPARATUS OF D. ALDRICH. 407 

Each of the tan vats H H' is connected with the adja- 
cent tan liquor tank L or L' by means of a short pipe 9 
filled with a stopcock h. These pipes do not open 
directly into the vat or tank, but connect with the ver- 
tical pipe 6 having closed the upper ends, but opened the 
bottoms, arranged close against the sides of the vat, and 
tank, like the pipes 6, with which the branches 5 of the 
liquor pipe and conduct pipe connect. 

These pipes 6 are fitted with three way cocks 2 like 
those 2 connected with the branches 5. The bate leech 
Jf is connected with the bate vat ^and bate tank Nhy 
similar pipes 9 and 6, and said pipes are furnished with 
similar stopcocks h and three way cocks 2, the said pipe 
6 running through the false bottom of the lime leech. 
The tan liquor tanks are each furnished with an air 
cock o in its cover for the admission of air, when neces- 
sary. The stopcocks 1 1 and h h are each surrounded 
by a boxing 4, which serves to collect any leakage, 
and by keeping these boxes filled with water, the cocks 
are rendered air-tight. 

The leeches /, M, and P, are each constructed with a 
false bottom 13, which is about two inches above the 
main bottom. The central portion of these false bot- 
toms is perforated ; but towards the sides of the leeches 
the said bottoms have an upward inclination, and the 
inclined portions are not perforated. 

The pool R, lime vat S, vats K, and handler I, each 
contain a cylindrical reel F, whose ends are composed 
of narrow, radial slats, and rings of wood, and whose 
sides are composed of narrow longitudinal slats and 
hoops of the same material. These cylinders have 
central shafts fitted to work in bearings in the ends of 
the vessels in which they are placed, and each is divided 
into four compartments by slatted partitions, as exhibited 



408 TANNING. 

in Fig. 97, in the handle 7; and each of these compart- 
ments is furnished with a hinged door, of the whole 
length of the cylinder, for the introduction of the hides. 

To provide for the rotary motion of the cylinder F, 
each of the vessels containing the said cylinders, con- 
tains also a pulley 12, which is secured to a short shaft 
working in bearings in brackets secured to one side of 
the vessel ; a band K is applied to run round the out- 
side of the reel. The shaft of the pulley 12 is provided 
at one end with a crank 6, which is connected by a short 
vibrating connecting rod h, with a vertical piston rod 
c, whose piston works air-tight in an upright cylinder 
14, attached to the lid of the vessel, said rod passing 
through the top of said cylinder, for the purpose of 
enabling it to be worked up and down by hand, or by 
suitable motive power applied outside of the vessel to 
promote a rotary motion of the pulley 12, and reel. 

Each of the tan vats H, H', contains a horizontal 
frame O, of wood, having slats extended from side to 
side, to hang the hides upon. Each of these frames is 
balanced upon the ends of the rockers e, e, attached to a 
rack shaft d, which extends across the vat, and works 
in bearings in the sides thereof The said shaft is fur- 
nished with an arm /, which is connected by a link m, 
bell crank lever n, and vibrating connecting rod p, as 
shown best in Fig. 99, with a vertical piston rod C, which 
works through a cylinder 14, attached to the lid a, of 
the vat, in the same manner as the piston rods by 
which the reels are operated. By working this rod, c, c, 
up and down, a reciprocating motion in a nearly hori- 
zontal difection is imparted to the frame Q. 

The process of tanning with this apparatus is con- 
ducted in the following manner : A number of hides are 
placed in each of the compartments of the reel F, in the 



TANNING APPARATUS OF D. ALDRICH. 409 

pool E, in which there must be sufficient clear water to 
keep the reel submerged ; and the same reel is then set 
in motion by power applied to its piston rod (7, and kept 
rotating for about six hours, or until the hides are per- 
fectly cleansed of dirt, blood, oil, or saline matter that 
may have been in them — the water being changed as 
often as it becomes dirty, during this part of the pro- 
cess, by allowing it to run off and introducing fresh water 
by pipes and cocks not necessary to be described here. 

From the reel F, of the pool, the hides are removed 
to the reel i^in the lime vat S, which then has its lid 
put on and secured closely, the lime leech having been 
charged with slacklime water, is introduced above the 
charge by suitable means not necessary to be described, 
and the lime vat S is placed in communication with the 
lime leech P, and with the lime tank 0, by means of the 
conduit pipes B, B, and its branches 5, by opening the 
stop-cocks 1, 1, and the lime tank is placed in com- 
munication with the air tank X, by opening the proper 
stop-cocks 7 and 8, in the branches of the air pipe E. 
Vent is then given to the lime leech P by removing its 
lid, leaving it loose ; and the air tank X, lime tank 0, 
and lime vat S are exhausted by setting the air pump 
W in operation ; and the lime vat S is filled with lime 
M'ater forced from beneath the bottom of the lime leech 
P, by atmospheric pressure ; said water passing up the 
pipe 6, of the lime leech, through the branches 5, and 
pipes B, into the lime vat S. When it is desired to 
strengthen the lime water in the vat S, the lime leech 
is put in connection, as before described, with the vat S, 
and put in direct communication with the lime tank 0, 
by opening the stop-cocks A, between them, after which, 
by giving vent to lime vat S, by opening its lid, the lid 
of the leech P being in the same time closed, and placing 



410 TANNING. 

the lime tank into communication with the air tank 
and starting the air-pump, the water is forced back into 
the lime leech P. For this operation the three way- 
cocks 2, of the pipes 6, in the lime leech should be 
turned to admit the water above the lime that it may 
percolate through it. The lime being thus strengthened 
may be forced back in the lime vat S, as before de- 
scribed. By the use of two lime tanks, 0, a constant 
circulation of liquor can be kept up through the lime 
leech P, and lime vat S', while the hides are in the 
lime vat S, the cylinder may be kept in motion con- 
stantly or set in motion from time to time. 

When the hides have been sufficiently limed they are 
removed from the lime vat S, and prepared for the 
bate, and put in the reel F, of the bate vat K, whose 
connection with the bate leech M, and bate tank M, 
and air tank is similar to the connection of the lime 
vat with its respective leech and tank, and with the air 
tank, and the operation of the bate vat is conducted in 
the same manner as that of the lime vat, the bate leech 
having been previously charged with bating material. 
Having been thus prepared for coloring the hides are 
placed in the reel F, of the handler /, which by open- 
ing and closing the proper cocks in the liquor pipes, A A\ 
and air pipe E, can be put in communication with the 
tan liquor tanks L L', and tan leech J, and the hides be 
operated upon in the same manner as in the lime vat 
and bate vat, except that tan liquor is used in place of 
the lime or leech liquors. 

After having been sufficiently colored the hides are 
suspended from the slats of the frames O G, in the tan 
vats H B.% and after the covers of said vats have been 
put on and secured, the tan vat R is connected with 
the tan leech J by one of the pipes A A, and its 



TANNING APPARATUS OF D. ALDRICH. 411 

branches 5 5, bj opening the proper cocks 1, 1, and is 
connected with its adjacent liquor tank L by opening 
the cock h of their respective direct connection pipe 9, 
and the said two liquor tanks L are, by means of the air 
pipe E, and its branches 9, brought into communica- 
tion with the air tank X, and the other tank liquor L' 
is, by means of the other of the pipes A' A', and its 
branches 5 5, brought into communication with the tan 
leech J. The pipe 6, of the tan leech, which is in con- 
nection with the tank L. having its cock turned to such 
position as to open the upper aperture of the said pipe, 
and the other pipe, 6, of the said leech having its cock 
reversed. Then by opening the cock 3, of the tank Z', 
and setting the air pump in operation to exhaust the air 
tank X, the liquor is forced by atmospheric pressure 
from the said tank L to the tank leech, where it falls 
upon and percolates through the tanning material and 
passes through the false bottom 13, from below, which 
is caused to pass by the opposite pipe 6 of the leech to 
that from which it enters, and the liquor pipe A or A'y 
to the tan vat H, By opening and closing the cocks to 
place the tan vat H' in the same relation to its respec- 
tive tank, and L, as just described, of jS^and L, and re- 
versing the above described relation of the tanks, L, X', 
with the tan leech and air tank, opening the air cock of 
L and setting the air pump in operation, the vat H 
may be filled from the tank L, by completely reversing 
the communication between the tan liquor tank, air 
tank, and tan leech from either of the above described 
conditions, the liquor may be returned through the tan 
leech ; and by a proper manipulation of the cocks, while 
the air pump is in operation, a cdhstant current of tan 
liquor through the tan leech, where it receives the tannic 
principle, and the tan vats where it is absorbed, may be 



412 TANNING. 

kept up. The reciprocating motion of the frames, G G, 
of the tan vats already described is kept up during the 
tanning process. 

The practical advantages derived from the use of an 
apparatus composed of a series of air-tight vessels with 
air pump and system of connection, such as above de- 
scribed, are as follows : It is well known to tanners that 
when a hide is limed in open vessels, and frequently 
exposed to the air, it becomes so hard and crusty that 
in order to soften it such a decomposing beating process 
is necessary, that the hide is brought so nearly to a 
putrefactive condition that its substance is materially 
changed, and it is not unfrequently seriously damaged, 
and it is also well known that in using tan liquors in 
open vats, the liquor readily absorbs the oxygen of the 
air and the tannic acid is so changed to gallic acid, which 
latter not possessing any tanning property, but having 
a dissolving e£fect on the fibre of the hide, thereby dam- 
aging its textile strength, and being of the same color 
as tannic acid, is a dangerous obstacle in the way of suc- 
cessful tanning; on the contrary, by using air-tight vats 
for liming, the change and loss in quality of the lime 
liquor is avoided, and by using such vats for tanning 
every species of chemical change in the liquor is avoided; 
and in bating the use of air-tight vessels is of no less 
advantage, as it permits the retention of all of the free am- 
moniacal gases, which gases perform so important a part 
in facilitating the neutralizing of any remaining lime in the 
hide, and cleansing the cuticle of all extraneous matter. 

By the use of the reel in the lime tanks the positions 
of the hide are constantly changing, and they are pre- 
sented to the action bf the lime liquor to the best ad- 
vantage, the hair and epidermis being loosened, and the 
hide being left in a naturally soft condition in a short 



TANNING WHEEL. 



413 



space of time. Corresponding advantages result from 
the use of the reel in the bate vat, and in the handler 
by the use of the reciprocating frames G, in the tan vats, 
the hides being suspended at a distance, a point just 
sufficient to permit the circulation of the tan liquor 
between them, are caused to be brought very uniformty 
and rapidly into contact with the tan liquor, the absorp- 
tion of which is thereby accelerated. 

By the use of the perforated false bottom, with in- 
clined sides in the leeches, the different substances are 
leeched by percolation, by which means from 15 to 25 
per cent, more strength can be obtained from tanning 
material than by either of the old modes of maceration 
or filtration. 



CHAPTER LXXYIII. 

TANNING WHEEL. 

This new apparatus, invented by V. E. Rusco, of 
Chicago, was patented in November, 1863, and has been 
used by many tanners, who consider it a great improve- 
ment. 

Fig. 100. 




414 TANNING. 

Fig. 100 is a view of a single wheel. Fig. 101 is an 
end view of the same, showing the internal arrangement 

Fig. 101. 



of the wheel and the hooks by which the leather is kept 
in motion. 

Fig. 102 shows how a number of wheels may be 
operated by one shaft and pulley. Any number of 
wheels can be driven in this manner, and each one can 
be thrown in or out of gear by means of a clutch and 
shipper. 

Fig. 103 shows how the wheel can be driven by a 
rope without the expense of a worm shaft and segments. 
This way of driving will answer when gear cannot be 
procured, but is not to be recommended either for dura- 
bility or economy. 

Fig. 100 is a perforated wooden cylinder, made of 
staves and hooped with iron bands; the ends of the 
cylinder are closed. In the inside of the cylinder are 
wooden hooks, in the form of a seekle, which keep the 
leather in motion as the wheel revolves. This wheel is 
best driven by a screw pinion working in a segment 
placed on the circumference, and when but one wheel is 



TANNING WHEEL. 
Fig. 102. 



415 




used in a tannery it should make from IJ to 2 revolu- 
tions per minute. When a number of wheels are used 
a slower motion is desirable. The small amount of 
power required to drive this wheel is greatly in its favor. 
No more power is required to operate ten of these wheels 
than it takes to operate one England wheel. The wheel 
is submerged nearly to its surface, and turning with a 
slow and regular motion, produces plump, firm, and yet 
very soft and pliable leather. Many first-class tanners 
give it as their opinion that the highest speed of other 



416 



TANNING. 
Fig. 103. 




wheels makes thinner shoulders and flanks than is made 
in the ordinary way of tanning ; while in the submerged 
wheel there is no strain to draw out the thin parts of 
the leather. 

When the hides are ready for the liquor they are placed 
in the wheel through trap-doors, which are closed and 
fastened. About 300 calf-skins, 125 sides of upper, or 
100 sides of harness is the capacity of a wheel, such as 
can be worked in a vat 9 by 10, 5 feet deep. Particular 
attention should be paid to running the liquor for the 
first two days in a green pack to draw a fine grain. The' 



NEW MODE OF TANNING SKINS. 417 

third run of a leech is quite strong enough. The vat 
should not be drawn down more than ten inches at a 
time two or three times a day for the first two daj^s. 
Draw the leather once a day for the first two days. 
After increase the strength and quantity of fresh liquor. 

After running a few days in the wheel the leather 
may be laid away in the ordinary manner. When laid 
a proper time it may be returned again to the wheel 
with great advantage. 

Care and judgment are necessary in proportioning the 
continual increasing strength of the liquor to the require- 
ment of the leather in the different stages of this process. 
The liquor should be kept cool, never to exceed 80°, too 
high a temperature with a strong liquor being highly 
injurious to the life of the leather. It is well known to 
practical tanners that a certain time is necessary to pro- 
duce a certain quality of leather. It is claimed for this 
wheel that it will save much of the labor, and greatly 
lessen the time in the ordinary way of tanning. If this 
wheel has no other merit than coloring, it should recom- 
mend it to all tanners. It also works equally well for 
bating and liming. Tanners will understand that it 
requires a larger wheel for liming, as the hides full up 
more. 



CHAPTER LXXIX. 

NEW MODE OF TANNING SKINS BY A LIQUOR OF TAR 
AND SOOT. 

Preparation of the Tan Liquor. 
Take 100 gallons of boiling water and throw into it 
from 18 to 20 pounds of good tar, add enough lime to 
form a thick paste. Pour cold water on to this compo- 

27 



418 TANNING. 

sition, to precipitate the lime in the form of a powder ; 
then add a pailful of tar and an equal quantity of pow- 
dered lime ; stir until you obtain a thick paste. 

Distribute this composition in several vats. ' The hot 
water is then drawn off from the kettle and poured in 
the vats — being careful to stir the composition three or 
four times with a shovel while you pour in the hot 
water. When the water is thus distributed cover the 
vats, and twenty-four hours after the liquor can be used. 

Preparation of the Soot Liquor. 

In a kettle for every 100 pounds of soot pour 55 gal- 
lons of water and 4 pounds of powdered lime ; stir three 
or four times during the filling of the kettle ; cover this 
kettle, and in twenty-four hours filter the liquor. 

Preparation of the Shins intended for Leather, 

The skins destined to be converted into polished 
leather are depilated and cleansed by the ordinary pro- 
cesses. They are then put in cold vats of oak-bark 
paste, and left in four or five days, and even a week. 
Handle them three or four times a day, and withdraw 
them. Dip them afterwards into the warm tar liquor of 
half strength, and increase gradually the strength until 
it has reached the primitive degree. Leave them fifteen 
days in this liquor ; put them anew in the oak bark as 
the first time, then in the weak liquor of tar. Handle 
them three or four times a day for the first two weeks ; 
place them in the strong liquor ; handle them twice a 
day, and leave them till they are well penetrated. This 
operation done, the skins are put, for a week or more, 
according to their thickness, in a warm solution of su- 
mach. Withdraw and dry them. 



INDIAN METHOD FOR PREPARING ELK-HIDES. 419 

Preparation of Leather for Soles. 

The hides are deprived of hair and flesh by the usual 
process. Put them for a few days in a cold vat of oak 
bark. Take them out and dip them as for polished 
leather ; introduce them into a vat containing a weak 
and warm liquor of soot — the degree of strength is about 
one-third or one-half of the primitive liquor. 

The skins are handled three or four times a day ; put 
them in a vat containing the warm liquor with all its 
strength ; handle them three or four times a day till well 
impregnated; dry them; dip them again, for half an 
hour, into a vat containing hot water. Brush and wash 
them well. 

The skins thus prepared are dipped in a strong solu- 
tion of oak bark. Handle them three or four times a 
day until the operation is achieved. Dry the skins every 
time they have been dipped in the last liquor. 



CHAPTER LXXX. 

INDIAN METHOD OF PEEPAEING ELK-HIDES. 

Immediately after the skin is taken spread it to dry ; 
take out the brains of the animal : which dry in the sun 
on the grass. When the hunting season is over the 
women prepare the hides by soaking them first in water, 
and afterwards taking off the hair with an old knife, and 
putting the hides in a large earthen vessel, adding to 
them the brains; then heat these hides to about 95°, 
which operation cleans them very well. They take the 
skins and wring them, without taking out the water 
entirely ; they spread them on a kind of rack composed 



420 TANNING. 

of two perpendicular posts and two sticks placed hori- 
zontally. With ropes they spread them well, and during 
the drying they rub them all the time with a stone or 
with a round piece of wood to expel the water and grease, 
till they are perfectly dried. The operation is then com- 
pleted. 

In one day a woman can prepare from eight to ten 
skins. 



CHAPTER LXXXI. 

HATCH'S PROCESS OF TANNING, CALLED ILLINOIS 
FRENCH TANNING, 

We mentioned that Mr. Hatch, of Princetown, Illinois, 
has taken out two patents for his process. The first was 
patented in 1856, and consists in preparing hides and 
transforming them into leather by using smoke of wood 
or its equivalent combustible, in the following manner : — 

The nature of his invention consists in smoking hides 
after being unhaired, and heated previous to putting 
them in tan, which changes the nature of the gelatine 
into an admirable condition for the rapid absorption of 
the tannin, and, at the same tinie, preserving the full 
texture and strength of the fibre, thus enabling him to 
tan calf-skins in from two to twelve days, upper and 
collar leather in from eight to twenty days, and other 
leather in a proportionate time according to the thickness. 
By smoking the hides and then handling them in su- 
mach, bran, and water, for half a day, and then putting 
them in alum, tan, and sumach, the tan struck through 
heavy uppers in three days. 

Hides prepared in this way preserve the gelatine in 
such a condition as to keep longer even poor weak liquor 



hatch's process of tanning. 421 

« 

devoid of tan. He uses smoke from various kinds of 
combustibles, all producing the same effect. 

Some of the great beneficial results in this kind of 
tanning are these : With a small capital he can compete 
with any tanner using bark; the. leather is better and 
more dur^lble. By using smoke in connection with 
tanning, it enables him to use terra japonica with or 
without acids in the tanning, with pretty good results. 
In the West, where no bark is to be obtained, he can 
successfully tan in much less time than in tan bark 
districts. 

That this principle of smoke, the great desideratum, 
is applicable in bark tanning, the world over in terra 
japonica, qy other tannin. By it he has been able to 
bring 8 lbs. of prepared hide through in 36 hours, cow- 
hide, upper leather, and collar leather in eight days, 
making good leather, yet he prefers from four to twelve 
days' time for tanning the same. 

The leather tanned by this process has been well tes- 
ted, and given good satisfaction. The method of operat- 
ing is as follows : The hides are bated in the usual way, 
either in hen bate, or wheat bran, as it leaves the hides 
more plump, until the lime is thoroughly worked out; 
after working it off the last time, they are rinsed in clean 
water to plump up, and open the hide fully wet, in order, 
while smoking, the grain may not become too dry, as well 
as to rinse off all uncleanliness ; then hang up in a tight 
smoke-room sufficiently large to hang up by but and 
neck, grain side out, then make a smoke in such a man- 
ner that the hides may not become heated from the fire. 
Smoke upper and collar leather hides six hours, other 
hides, time according to thickness, then take them out 
and soak them an hour in clean water, to assure the 
hides a fully wet condition, before coming in contact with 



422 TANNING. 

t 

tan ; then put them in tan ooze of moderate strength. 
Stir, and handle often, until the grain is colored even 
and struck through, then increase the strength of the 
ooze, by tannin from day to day, until the hides are 
tanned. 

To get a light color in the terra japonica or hemlock 
ooze, add a little sumach in the first, handled in such 
proportion as half a pound per side for upper leather. 

For heavy leather, such as harness and sole-leather, 
after being prepared in the usual way, should be smoked 
six hours, then soaked in clean water one hour, then 
smoked again six hours, soaked again, and passed in 
tan as above stated. 

As regards the above process on smoking, or preparing 
hides for tanning, the author says : " I am well aware 
that smoke has been used in dressing glove leather, out 
of deer-skins in the old Indian manner, but not used in 
the manner, and for the purpose, as I use it under the 
patent, namely, in preparing hides for tanning, to tan 
with any vegetable tanning astringent." 

The novel application of smoke, as done under this 
patent, has the following great and desirable effect on 
hides ; It toughens the epidermis, retains and coagulates 
the albumen, permeates, toughens and preserves the 
gelatine and fibrin, and disposes them to readily unite 
with tannin, producing leather rapidly and of great 
firmness. It also plumps up the flanks and shoulders of 
leather, causing them to readily fill up with tannin; 
therefore much better weight to the profit of the tanner 
and also to the worker of leather ; as they are enabled 
to cut out more solid, serviceable leather than is gen- 
erally obtained from old fashioned tanning. The leather 
also generally retains its pliability and smoothness 
longer in wear through all kinds of weather. The tan 
liquors also become impregnated with the potent prin- 



hatch's process of tanning. 423 

ciple and are thereby rendered in preserved condition so 
that they do not sour, thereby a great saving of tannin. 
As in the old way of tanning fresh tan liquors are often 
drawn off into vats of sour liquor, or the latter is drawn 
off into leeches of pure fresh tan, thereby the sour liquor 
precipitates a portion of the tannin in flakes to the 
bottom of the vat, in this manner much tannin is ut- 
terly lost to the tanner and the country, the saving of 
which alone, by this simple and almost costless improve- 
ment, is no small item. Hides but slightly tanned have 
been known to keep a long time in a perfectly sound 
condition in ^uch impregnated liquors devoid of tannin, 
this improvement thus preventing damage by decompo- 
sition of hides in process of tanning, when the tanner 
may happen to be deficient in supply of tanning material. 

The best results from this improvement are seen in 
oak bark or japonica tanning. This system, now called 
Illinois French tanning, lately reorganized on the pre- 
vious and following process, reconstructed and systema- 
tized since 1858. The system, as now organized, having 
other very important filings in ingredients and a method 
not here, nor ever yet made public, or communicated to 
any but the purchasers of the process. 

The melilotus, or trefoil plant, mentioned in the follow- 
ing process, is a very useful and cheap plant in tanning; 
it is a substitute for the imported Sicily sumach ; besides 
possessing equal and similar coloring matter it also pos- 
sesses certain saccharine properties that sumach does not 
contain. It gives valuable conditions to leather, a beau- 
tiful oak color, softness, toughness, and a cheesy con- 
dition; it rectifies terra japonica in leather, so as to 
modify its caustic nature and entirely do away with the 
japonica smell, giving leather a pleasant aromatic odor. 
The proportion of the plant in the system is small ; it 
is a hardy, rapid growing plant on low damp soil, 



424 TANNING. 

yields heavily, producing from four to six tons per acre, 
and two yearly crops from one seeding. 

All other cloves or grasses have a weakening effect on 
leather, causing it to be thin and flanky, and to suffer a 
great loss in weight. The melilotus in effect is to the 
reverse of all that, and favors all the desirable conditions 
in leather. 

This new process was patented in 1861, and consists 
in the use of the sweet-scented clover [Melilotus), in con- 
nection with terra japonica, cutch, tan bark, or other 
material used in the tanning of or manufacture of leather. 
Mr. Hatch operates as follows : He extracts the virtue 
from the melilotus by steeping in water, or tan liquor, 
and mixes the same with the terra japonica, cutch, or 
other tan in the proportion of 4 pounds of the green, or 
2 pounds of the dry plant to each side of upper leather, 
or according to heavier or lighter stock — measuring 
the amount of melilotus to the proportion of tan used, 
as greater softness or toughness of leather is desired ; or 
decreasing the proportion of melilotus as greater firmness 
of leather is desired. Put the raw hide into the liquor 
of said melilotus, and tan combined, or into each sepa- 
rately — changing from one to the other until tanned; 
and also drench tan leather in the liquor of said meli- 
lotus to soften it, and likewise to improve the color to 
that of oak-tanned leather. 

The plant should be gathered when in flower, or when 
about going into flower. 

It is a well-known fact that terra japonica, and cutch, 
are powerful astringents, and that, used alone, tend to 
make leather harsh and brittle, and thus liable soon to 
crack and break to pieces in wear ; but, using the meli- 
lotus plant in connection with them, has an admirable 
effect in neutralizing their harsh nature, and thus to im- 
prove their condition in tanning leather. 



PROCESS OF MANUFACTURING LEATHER. 425 



CHAPTER LXXXII. 

IRISH PROCESS. 

In 1766 Mr. Kankin announced that the -heath, which 
is very common in Ireland, contained a tanning principle 
susceptible of taking the place of oak bark. Several ex- 
periments having succeeded, he published the following 
process : He puts the heath in a large kettle full of water, 
and leaves it to boil three hours, which time is sufficient 
to exhaust it. He decants this water in large vats which 
must be fixed in such a way that the water can be ex- 
hausted a second time. Be careful to put the si^in in 
this last water when the temperature has fallen at 95°. 
This method tans the skins more easily than in the ordi- 
nary process. The solution of heath must be changed 
often; and, when used, the temperature must not be 
higher than 95°. This process gives a good tanning. 



CHAPTER LXXXIII. . 

PROCESS OF MANUFACTURING LEATHER CALLED CUIRS 

A MURON. 

When the hides are fresh, soak them for eight days 
in particular wells, or in the river; draw them out 
every day to soften them. When they have been suf- 
ficiently soaked, take them out and put them in a 
solution composed of two parts of ashes and one of 
quicklime ; dissolve the ashes and lime by boiling water, 
stirring all the time. Afterwards pour this mixture in 



426 TANNING. 

a vat, dilute it with the necessary water, and soak the 
hides in it. Not to have them in contact with the resi- 
duum, which always settles to the bottom, cover it with 
a grate. Leave the hides in it until the hair can be pulled 
easily, which is generally the case after eight days. Take 
them out and depilate them with the round knife. Then 
tie the skins two by two, suspend them to poles, and 
place them in a current of water to cleanse them entirely 
from ashes and lime. Let them drain, flesh them, and 
trample upon them with the feet. 

The small hides are put in a mixture called hahscha, 
composed of warm water and dog dung. Leave them 
to soak for twenty-four hours ; take them out, clean, and 
wash them ; macerate them in a liquor composed of oat 
flour and malt; leave them twenty-four hours. Put 
them *n tan water, where they stay three days j after- 
wards they are worked in the following manner: Fill 
the vat half with pure and half with tan water ; lay 
the hides pn the grate, after having covered each one 
with powdered oak bark : the little hides may remain 
eight days; leave the strong and thick ones a longer 
time. When you draw the hides empty that vat, wash, 
trample the hides with the feet, wash, and flesh them ; 
repeat the same operation four times, being careful to 
cover each time the skins with oak bark; the fourth 
time leave the skins in the vat for three weeks. When 
they are sufficiently tanned, they are spread two by two, 
and as soon as they are dry they are sent to the currier. 

For red leather they generally take buckskins and 
calf-skins of every age. The red leather is dyed with 
red sandal-wood, and the black with logwood. A large 
skin requires 1 lb. of sandal; J lb. is sufficient for 
a small hide. To dye 100 hides black, dissolve with 
the logwood 3 lbs. of green vitriol ; and for 100 red 



KALMUCKS' PROCESS. 427 

skins 3 lbs. of alum. Before dyeing the skins, give them 
the form of bags, leaving only a small aperture to mtro- 
duce the dye ; shut this opening, and shake the skin in 
in every way. This done, leave the skin to dry, and 
give it a second and even a third dye. When the skin 
is colored enough, coat it on the flesh side with birch 
tan or whale oil. 



CHAPTER LXXXiy. 

KALMUCKS' PEOCESS. 

With the Kalmucks, the women have the charge of 
tanning the hides. To prepare the skins of young lambs, 
they wash them in tepid water, spread them in the open 
air, and keep them till nearly dried, then they flesh 
them, and expose them anew to the air on the grass. 
During three days, they coat them three times a day 
with sour milk, in which a little salt is dissolved ; the 
fourth day the skins are dried, and are worked all over 
with the hands, until entirely supple. 

To have the hides resist the dampness and rain, they 
are smoked ; for this purpose, a fire is lighted in a little 
vat, on which rotted wood, dry manure, etc., are thrown. 
They also use sheep dung, and the stipa ca]pillata. 

All round the pit they plant sticks disposed in form 
of pyramids, which are covered completely with the 
skins destined to be smoked. From time to time the 
position of the skins is changed from top to bottom. 
They continue thus, for one hour, then they work them 
to render them supple ; they are rubbed on the flesh side 
with chalk, or gypsum ; they are polished with knives, 
bleached anew with chalk, and well beaten. 

Buck, and sheep-skins, destined to make riding pants. 



428 TANNING. 

or travelling summer dresses, are prepared in the follow- 
ing manner. The fresh hides are rolled, and left in a 
corner, until the wool, or hair, can be pulled; they are 
coated with sour milk, and worked in the same manner 
as lamb-skins ; then they are spread on the ground, and 
the flesh side is coated with a strong decoction of statice, 
to which alum, and a certain quantity of mutton suet 
are added, then they are dried. Begin again the opera- 
tion until the color of the root has exactly penetrated 
the skins. The hides thus prepared resist the dampness 
well. 

The Kalmucks who live on fish, skin the large sea 
carp, dry the skin, remove the scales, and tan it after- 
wards. For this purpose they use sour milk, or a decoc- 
tion of statice. These hides are almost transparent, and 
are used to make hoods as a protection against the rain. 

Nearly all the house utensils of the Kalmucks are 
made from leather. For this purpose they use ox, and 
horse-hides. The back part is considered the best. To 
prepare them, they heat them in boiling water until the 
hair can be pulled off, others depilate them with ashes, 
afterwards they flesh, and wash them in running water. 
When withdrawn from the water, they are spread in the 
sun. Before being dried, they are cut into pieces, to 
which the intended form is given, and those pieces are 
sewed ; the form is then given, and they are dried before 
a fire. 

Those vessels have a very disagreeable odor, which com- 
municates to everything which is put in. They soften 
by the introduction of a liquid too cold or too warm. 
These defects are obviated by exposing them to a heavy 
smoke for several days; by this means they take the 
appearance of horn, and have a solidity so that they can 
be kept many years without injury. 



LEATHER MANUFACTURE IN TURKEY. 429 



CHAPTER LXXXV. 

LEATHER MANUFACTURE IN TURKEY. 

The chief manufacture of leather in Turkey is in 
Trebizond, Mosul, Amaziah, Constantinople, and Ter- 
nova. The colored goat and sheep-skins, generally used 
to make slippers, come from Diarbeker, Aleppo, Damas- 
cus, Mecca, Smyrna, Sarohan, Kutahiah, Seras, UskufF, 
Salonica, Philippopoli, Tirhala, Scyros, Randos, Eukare, 
Rustchuck, Widdin, Constantinople, and Erzeroum. 
There are great varieties of these skins. The red and 
the yellow are brilliant and solid ; they are used chiefly 
for slippers, especially the latter color, which is usually 
reserved for Turkish ladies. The red and the black are 
much sought after for the making of saddlery of the 
oriental fashion. 

All these skins, and more particularly the sleeked 
cow, are usually a little too dry; they have not suffi- 
cient flexibility, nor are they thick enough. These de- 
fects arise chiefly from the imperfect tanning processes 
employed in the provinces. The sheep and goat-skins 
are well curried. 

It is known that the European process of tanning 
lasts a long period. None of the attempts made in 
Europe during the last 30 years to discover means 
whereby to expedite the operation of tanning have 
completely succeeded. The hide must remain, on an 
average, at least one year in the pit before it becomes 
properly tanned, and the preparatory operations to 
which the hides must be subjected before the process of 
tanning is entered upon are also quite long and compli- 



430 TANNING. 

cated. They are divided into cleansing, swelling, depi- 
lation, and table work. Then comes the operation in the 
vats and pits. 

A tannery is built quite close to a river, or to a spring 
of water able to furnish all the water necessary in these 
various operations. 

The hides are first of all carried to a river and plunged 
in the water during half a day in order to wash away 
the bjlood and dirt with which they are soiled. Care is 
taken to turn and stir them from time to time, and they 
are rinsed before being taken out of the water. Dry 
hides, of course, need to remain longer in the water than 
fresh skins. These are briskly washed several times 
each day, and they are stretched with the stretching 
iron, trampled under the feet, cleansed, and the water 
then allowed to drain off. They are also worked 
once or twice at least with a round knife, having no 
edge, in order to stretch them perfectly, and to clean 
and soften them, the fleshing having been previously 
done ; cellular tissue, the viscous matter, the muscular 
fibres, and in general all those parts which are apt to 
putrefy readily, are removed. 

After the skins have been sufficiently softened they are 
replaced in the water and allowed to remain there from 
five to six hours. Care is taken not to let them remain too 
long, especially if the water is not fresh and running, for 
too long a stay in the water brings about a putrid de- 
composition of the hide, which afiects it more or less 
deeply. However, all species of water are equally suit- 
able for this operation, provided that the hide is only left 
therein long enough to wash it thoroughly, the sole 
object being to cleanse it and remove all hardness and 
stifihess. It has been ascertained by experience that 



LEATHER MANUFACTURE IN TURKEY. 431 

hard water is more suitable when heavy leather is to be 
produced, and soft water for soft leather. 

The second operation to which hides are subjected is 
the swelling or raising. The method used in the Otto- 
man provinces is a preparation of barley in a warm vat. 
According to this method as soon as the hides have been 
softened in the water they are trampled under the feet, 
and the round knife, above mentioned, is passed over 
the flesh side to make them supple. Then they are 
cleaned and placed on poles to drain. They are next 
examined to ascertain whether the hair comes off readily 
from the skin, which may appear in summer without 
further preparation. When fresh hides are treated they 
salt them without soaking them by sprinkling them with 
about 5i lbs. of a mixture made up of sea salt, alum, 
and saltpetre. Then they pile them up and lay a mat 
over them. 

Hides thus arranged speedily become heated, and they 
are turned over several times each day so that the fer- 
mentation may take place uniformly in all parts, and 
when it is perceived that the hair will come off easily it 
is at once removed as a too prolonged fermentation will 
damage the flesh side of the hide. 

As soon as the depilation is completed the swelling is 
begun. For this purpose they make a leaven of wheat 
which is securely covered and kept in a warm place. It 
takes 24 hours to prepare this leaven. In swelling the 
hides a vat is used, which is partly filled with water. 
Then a few pailfuls are drawn from it and boiled, and 
in this boiling water are mixed 681 lbs. of barley, 
coarsely ground, made into a paste of the consistence of 
a thick glue by the admixture of cold water; then they 
put the paste back into the boiler and let it boil tho- 
roughly, stirring it incessantly with a stick. After it 



432, TANNING. 

has risen three times they pour it into the vat and stir 
the contents with a wooden shovel, turning always to 
the one side. 

The vat is then very carefully covered after having 
taken out two pailfuls of the liquid that it contains, 
which is placed on the fire, and as soon as this composi- 
tion begins to bubble they mix in the wheat leaven first 
made and pour the whole into the vat. This constitutes 
the first operation, which is intended to do for 6 or 7 hides. 
Such a temperature should be maintained that the work- 
man cannot bear his arm in it without pain. They 
then add 5Hbs. of sea salt ; mix the whole well together 
and let it sour during 15 days, taking care to stir it 
several times each day, and to cover up the vat again 
immediately thereafter so that it may lose none of its 
heat. 

At the end of that time the hides are thrown into a 
spring together by threes on a rope, and they are left 
there from four to five days. Each day they are taken 
out twice, rinsed, drained a little, and then put back ; 
and this operation is kept up until the flesh side of the 
hide becomes soft enough to retain the imprint of a 
finger nail, when the finger is pressed against it. They 
are then taken out to be fleshed, and if any hair remains 
it is shaved ofl", after which they are rinsed in clean 
water and laid to drain upon poles during twenty-four 
hours. 

A second leaven of wheat is then made, a little 
weaker than the first. The sour liquor, which was used 
in the first operation, is next poured out, keeping only 
the clear portion of the liquid, which is poured into a 
second vat in order to receive its complement ; that is 
to say, the addition, as in the first operation, first of a 
quantity of ground barley, a little less than the first, 



hannote's process. 433 

then of the second leaven already prepared, and finally 
of a little sea salt. Thus two vats are prepared for the 
operation. Care is taken to withdraw a few pailfuls, 
which are kept in reserve on the fire ; and when the 
fermentation is well established, which is ascertained by 
the sourness of the water, the hides are removed from 
the framework of poles to plunge them in, for a minute 
or two, that they may gradually acquire the temperature 
of the vat. They are then laid on the cover of the vat 
so that they may drain off a few minutes without be- 
coming cold; then they are pressed down into the vat, 
and after it is covered again the heat is kept up by the 
aid of the hot water held in reserve. At the end of a 
quarter of an hour, the hides are taken out for the 
second time, and are allowed to drain in the same man- 
ner as before during a quarter of an hour, after which 
time they are again plunged into the vat and left there 
half an hour. 



CHAPTER LXXXVI. 

J. HANNOYE'S PROCESS. 

Another method, analogous in principle to the pre- 
ceding, consists in producing an equable and active 
filtration of tan-liquors through the skins, while they 
are exposed to pressure, the kind, temperature, strength, 
and mode of employment of which can be varied at will. 
For this purpose, the filter-press of Real, with some 
modifications, is made use of, not merely with the inten- 
tion for which it has before this been employed, of ex- 
tracting the active principles of bark, but as a direct 
agent in the tanning process itself; the skins being stra- 
28 



434 



TANNING. 



tified in it with layers of bark, and the extraction of the 
tannin, and the absorption of it by the skins, being both 
ejBfected under pressure, and without contact of air. The 
apparatus, which has been prepared upon the principle 
of the filter-press, is provided, like it, with a tube having 
air-tight joints, by means of which a forced and uniform 
filtration is effected by the pressure of a column of fluid, 
and the tube is of such a height that the pressure can 
be increased or diminished at pleasure by altering the 
height of the column, while the character of the opera- 
tion can be varied at will by the employment of different 
fluids. The pressure of the column of fluid can be 
directed alternately upon either the upper or lower sur- 
faces of the skins, by means of tubes provided with stop- 
cocks, and entering the vessel at the top and bottom. 

The inventor claims this new application of the prin- 
ciple of the filter-press, as being entirely original, and 

Fig. 104. 




M 1X1 Ixf-^^'M M M .1x1 fxl' 



asserts that, by the employment of it, he has been able 
lo arrive at a perfection, rapidity, and exactitude of the 



hannote's process. 



435 



method of tanning, which have not been attained by any 
other process. 

Figs. 104, 105, 106. Vessels of.a cylindrical or square 
form, of a suitable capacity to hold the number of skins 



Fiff, 105. 



^ 



IL 



^ 



rii 



u 
li 
n 






bT] 



intended to be operated upon, and which are capable of 
resisting a considerable pressure. A tube a, «, Fig. 104, 

Fig. 106. 




mim mrriTTi nTn mmm 

'a-IUJ L_l 1_1 L-l L-l I— I I— I I— ' 1—1^ 



i irim m m m r~» rn m m miV 



UJL. ^*M tXl ' VU I 



il?nm n m m n m »n m mr^n 




is attached to each, and is proportioned in height to the 
mode of making pressure which is to be adopted; whether 
it be that of a column of watery ifluid, of mercury, or of 



436 TANNING. 

the hydraulic piston. Branch-pipes h, h', connect this 
tube with the upper and the lower part of the reservoir, 
and the opening of one or the other of the stop-cocks 
upon them causes the pressure and consequent infiltra- 
tion of tan-liquor through the skins to take place either 
from above downwards, or in the opposite direction. 
A pipe with a stop-cock e, allows the liquid within the , 
vat to escape. 

" The reservoir may be composed of different materials. 
It may be constructed of solid masonry, covered in its 
interior with lime cement, over which a coating of tar 
or of some resinous substance is placed, so as to defend the 
leather from the action of the lime. It may be made of 
wood, lined with sheet-lead ; zinc or copper, well soldered 
in all parts; or may be composed of cast-iron, lined 
throughout with lead or zinc, so as to prevent the injuri- 
ous effect of oxide of iron upon the leather. In either 
case, the rim of the neck of the vessel consists of a solid 
plate or disk of metal, firmly attached to it, and a disk 
of thick leather is interposed between it and the top or 
lid, which is tightly fastened down by means of screws 
and nuts upon the plate. This top may consist of thick 
wood or of metal plate, also lined on its lower surface 
with sheet-lead or zinc. The copper or leaden tube d, d^ 
for the column of fluid, is from one to three inches in 
diameter, and is connected with the vessel by two tubes 
/, /', one entering it below the lid, the other at its 
base. By opening the stop-cock upon the upper tube, 
the pressure of the fluid is made upon the upper surface 
of the skins, and in the opposite direction by opening 
that upon the lower tube. Two other cocks, g, g', the 
one proceeding from the lid, the other from the lower 
part of the reservoir, conduct the liquid which has tra- 
versed the skins into a suitable receptacle, the upper one 



hannote's process. 437 

being left open when the pressure is from below, and the 
lower one when it proceeds from above. The skins are 
stratified in the vat between beds of tan ; water alone is 
usually employed for the pressure upon its contents, and 
for the extraction of the tannin, and the cocks for the 
egress of fluid are only left so much open as to allow it 
to escape drop by drop. 

"Calf-skins may be tanned in twenty days by this 
method, and ox-hides in sixty days, but the tanning 
may be much expedited by the following arrangement : 
Instead of simply stratifying the skins with layers of 
bark, a framework of wood, with an open space in its 
interior, rather smaller than the skins, is placed upon 
each one. The interior of this frame is filled with tan, 
another skin is extended above the frame thus filled, 
and is in turn surmounted by other frames and skins 
arranged in the same manner. To prevent the fluid 
from being forced through the spaces between the out- 
sides of the frames and the walls of the vessel, these are 
filled up with mastic, or some impervious cement like 
the fatty lute of chemists, or a mixture of tallow and 
rosin. A similar application of lute is made around the 
edges of the skins, and the weight of the tan and frames 
soon makes the cemented parts perfectly tight. 

" After each tanning is completed, the mastic or luting 
can be taken off and used for a similar purpose again. 
Skins tanned by this last method are as perfectly pre- 
pared in a few days, as those which have been exposed 
in the pits for sixteen months." 



438 



TANNING. 



CHAPTEK LXXXYII. 

, M. NOSSITER'S PROCESS. 

This new method was patented in England in 1844, 
and consists in depositing the skins in pits so that they 
shall not be subjected to the pressure of those placed 
above them, and in pressing out the exhausted infusion 
contained in them, before immersing them again in fresh 
ooze. 

1. The skins being superposed, in the old method of 
tanning in vats, those which are below are so compressed 
that the tan-liquor penetrates their structure with diffi- 
culty. To avoid this objection, the inventor proposes to 
deposit the skins in square vats, and to separate them by 
the interposition of rectangular frames with ledges. By 
this means the skins are perfectly free from contact with 
each other while in the tan-liquor. 

Fig. 107 represents a horizontal section of the vat, and 
a frame with a skin stretched over it. 

Fig. lot. 




Fig. 108 is a vertical section, showing the frames in 
stack, and the skins between them. 



nossiter's process. 

Fiff. 108. 



439 




Fig. 109 shows the plan of the bottom of the vat. 
Fig. 109. 



(|IJ U U U U U U U U U LI U L _ 



Fig. 110, plan of the frame. 

Fig. 110. 




a^ a. Vat, of the ordinary form ; &, h, wooden frame, 
with crosspieces ; 5', ledges for maintaining the pieces in 
position. 

This method of tanning is much more expeditious 
than the old way; for although fewer skins can be tanned 
by it at one time, it admits the working of a greater 
number in a given time, and in the same vat. 



440 



TANNING. 



The vat is first filled with the skins and frames, and 
the tan-liquor is then introduced. When this latter is 
exhausted or weakened, it is pumped out and replaced 
by fresh ooze. 

The skins are deprived of exhausted liquor, in many 
establishments, by pressure between rollers ; but as this 
method does not fully effect the object, Nossiter subjects 
them to the action of a screw-press, which is seen in 
vertical section in Fig. Ill, and in the plan. Fig. 112. 



Fig. 111. 




This press consists of a strong rectangular support /, 
from the four corners of which arches spring, which 

Fig. 112. 




meet in the centre in a square nut h, in which the strong 
screw i turns. The skins are placed above each other 
on the table of the frame, and are pressed by the plate 



NOSSITER S PROCESS. 



441 



Z:, at the lower end of the screw, which is turned by the 
lever I. The skins are subjected to this pressure until 
all their fluid contents are expelled. 

Fig. 113. 




In place of the screw-press, one with an axle, seen in 
Fig. 113 in vertical section, and in Fig. 114 in plan, may 

Fig. 114. 




be used. Around the axle m, the cords n, n, are rolled, 
which pass through pulleys in the supports. The cords 
are passed at their ends through screw-rings on the sides 
of the under surface of the plate p. By turning the 
axle with the lever g, the upper plate is made to com- 
press the skins which are placed below it. 



442 



TANNING. 



CHAPTERLXXXVIII. 

SQUIRE'S PEOCESS. 

This process, patented in 1844, consists in depositing 
the skins in a horizontal wooden cylinder, which is made 
to revolve slowly, under the surface of hot tan-liquor, so 
as to insure constant agitation of the hides and skins, 
and perfect exclusion of air. 

Fig. 115 represents a transverse vertical section of the 

Fiff. 115. 




apparatus, as placed in the vat : a, wooden drum 12 feet 
long and 7 feet in diameter, lined with ridges, and divided 
into four compartments by the partitions b, h, which are 
composed of wooden staves, or bars with open spaces 
between them. Hot ooze, and some of the tanning ma- 
terial are then introduced with the prepared hides 
through a water-tight door c. The vat should be deep 
enough to admit the submersion of the whole cylinder, 
which is to be kept in uninterrupted motion, at the rate 



PROCESS TO TAN NETS, SAILS, AND ROPES. 443 

of six or seven revolutions per minute ; and for this pur- 
pose its axle d, resting upon upright supports, is turned. 

This is really an accelerating process, for the use of 
hot ooze, and the continuous contact of the skins with 
the tan-liquor, vshorten the time for complete tanning to 
two weeks. Moreover, it permits the use of divi-divi, 
catechu, and other readily oxidizable tanning materials, 
which, when used in open vats, color the leather and 
render it unsalable. The access of air in this process 
being limited, this disadvantage is avoided. 

The ooze spends its force very rapidly, and must be re- 
placed by fresh hot liquor as fast as it becomes exhausted. 



CHAPTER LXXXIX. 

ENGLISH PEOCESS FOR TANNING NETS, SAILS, AND ROPES. 

The following method of preserving, and increasing 
the strength of nets, sails, and ropes, has been proposed 
by a shij) builder of Bridgeport. He boils, in 89 gals, of 
water, 100 lbs. of oak branches, and the same quantity 
of tan, until it is reduced to 71 gals. He decants the clear 
liquid, and introduces into it the articles to be tanned, 
being careful to have them entirely covered, and not 
touching the bottom of the vessels. He boils them three 
hours, withdraws, and dries tliem. 

This is not a regular tanning process; its object is only 
to combine the tannic and extractive matter with vege- 
table substances, which are very different from the gela- 
tine of the skin. Linen, steeped two or three days in a 
solution of oak bark at the temperature of 150°, was 
kept in a damp cellar for ten years, without being rotted, 
while an untanned piece, placed in the same circumstan- 
ces, was completely rotted. 



444 TANNING. 



CHAPTER XC. 

EXPERIMENTS IN THE TANNING- OF CALF-SKINS WITH 
TAN, DIVI-DIYI, CATECHU, AND ELECAMPANE BARK, 
BY M. KAMPFFMEYER. 

These interesting experiments were published in the 
Memoires of the Societe d' Encouragement of Berlin, and 
the Technologist. We shall describe them with details. 

To proceed to these experiments, twenty-five calf-skins 
were chosen ; they were identical as nearly as possible. 
Of these twenty-five skins, seven were tanned with oak 
bark, six wfth the elecampane bark, six with catechu, 
and six with the divi-divi. 

The twenty-five hides, during the operations, were 
submitted to the same manipulations. When those 
manipulations were finished, all the skins treated by the 
sulphuret of calcium and by the lime were cleansed as 
much as possible from the lime, and deposited in the 
vats. 

Oah Barh. — Amongst the skins tanned with this 
bark the three pieces treated with sulphuret of calcium 
weighed, when raw, 12 lbs. 14 oz. ; weighed anew, after 
the tanning, and passed to the tallow, they weighed 12 
lbs. 5 oz., consequently they had lost 9 oz. There had 
been used 84 lbs. 2 oz. of bark; that is, 6 lbs. 8i oz. 
of tan per pound. 

The four skins treated by caustic lime weighed, when 
raw, 14 lbs. 11 oz. ; after tanning they weighed 13 lbs. 
14 ounces, consequently they had lost 13 oz. They 
required 107 lbs. 12i oz. of tan; that is, 5 lbs. 8 J oz. 
per pound. They were similar to the commercial leather, 
and their grain was finer than in the other experiments. 



kampffmeter's process. 445 

The skins treated by sulphuret of calcium were firmer 
and soft.. 

Divi-Dim. — The three skins treated by the sulphuret 
of calcium weighed, raw, 12 lbs. ; when tanned, they 
weighed 11 lbs. 3 oz. ; they had lost 9 oz. They required 
] 3 lbs. 2 oz. of divi-divi; that is, 1 lb. Hi oz. per pound. 

The three skins treated by caustic lime weighed, raw, 
10 lbs. 8 oz. ; and when tanned, 9 lbs. 15 oz, ; they had 
lost 9 oz. They had required 11 lbs. 3 oz. of divi-divi, 
or 1 lb. Hi oz. per pound. 

The edge and the color were very fine, and the tanning 
more satisfactory than in the other skins. The grain 
had not so fine an aspect as the skins tanned with oak, 
but it was satisfactory. 

Catechu [Terra Jajponica) . — The three skins treated by 
sulphuret of calcium weighed 9 lbs. 10 oz.; and after 
tanning, 11 lbs. 13 oz. ; they had thus gained 2 lbs. 3 
oz. They required 13 lbs. IJ oz. of catechu, or 1 lb. 21 
oz. per pound. 

The three other skins treated by lime weighed 12 
lbs. ; when tanned, they weighed 12 lbs. 4 J oz. They 
had gained 4i oz. They required 13 lbs. Ih oz. of 
catechu, or 1 lb. 4i oz. per pound. 

The tanning was perfect ; the color slightly orange ; 
the side was unequal and rough ; the grain was thin and 
spongy in the skins treated by quicklime. They were 
inferior to the others. 

Elecampane Bark. — The three skins treated by sul- 
phuret of calcium weighed, raw, 11 lbs. ; and when 
tanned, 11 lbs. 4i oz. ; they had gained 4 J oz. They 
required 155 lbs. 3 oz. of bark; that is, 14 lbs. li oz. per 
pound. 

The three skins treated by quicklime weighed, raw, 
10 lbs. i oz. ; and when tanned, 9 lbs. lOh oz. ; they had 



446 TANNING. 

lost 6 oz. They had required 121 lbs. 5 J oz. of bark, 
or 6 lbs. 2 oz. per pound. 

Notwithstanding the large quantity of bark, the skins 
were more or less imperfectly tanned — principally those 
treated by the sulphuret of calcium ; they were so hard 
and dense that the grease could not penetrate them 
entirely; the grain was flat. The skins could be tanned 
easily even after the greasing ; their color was brown. 

We see by the above experiments that the tanning 
with oak bark and divi-divi were the best, and the latter 
can be compared with the oak. 

The use of catechu, as a dry matter in the tanning of 
skins, is inadmissible. The porous and thin texture 
of the leather thus manufactured is a poor guarantee 
against dampness and permits of little duration. 

The results obtained with the elecampane bark are 
less satisfactory. 

For the expenses, there is little difference between oak 
bark and divi-divi. Divi-divi, it is true, is more costly ; 
but as it possesses six times as much tannin as oak bark, 
the balance will be rather in favor of the latter. 

Trials were also made with green Buenos- Ay res hides, 
and the results were about the same as above. The 
divi-divi is superior to catechu and elecampane, and can 
be compared to the oak in many respects ; but it requires 
more care in its use on a large scale, while the operation 
is one-third shorter. 

According to the author, the divi-divi is the best 
substitute for oak ; and while it is difficult to grind it, 
reduced into the form of an extract it. can be advantage- 
ously employed by its mixture with oak bark. 



turnbull's process. 447 



CHAPTER XCI. 

TANNING HIDES, BY J. W. JOHNSON. 

Mr. J. W. Johnson proposes to employ for the pur- 
pose of tanning hides a new vegetable decoction prepared 
from Maruta Cotula, to a gallon of which are added 4 
ounces of catechu and 2 ounces each of common salt 
and alum. In this mixed tan liquor, the skins or hides, 
with or without hair upon them, are to be immersed, 
and there left for a period determined by the thickness 
of the hide, and by other circumstances which ordinary 
experience will dictate. 

Sir Humphrey Davy was the first to show that catechu 
alone could be employed as a tanning material. We are 
unacquainted with any special property possessed by 
the vegetable decoction referred to, which would render 
advantageous its employment in conjunction with the 
foregoing. 



CHAPTER XCII. 

TURNBULL'S PROCESS. 

The Technologist has given, on this process of tan- 
ning, details that we propose to reproduce here. 

In the tanning of skins, as every one knows, it is very 
difficult to bring the tannin immediately in contact with 
the gelatinous matter of the skins, and that for the 
following causes : — 

* Sixth year, page 442. 



448 TANNING. 

1. Hides macerated in lime absorb a certain quantity 
of this earth, which takes a portion of the gelatinous 
substance in form of soluble gelatine, that is, alters the 
fibre enough to render it incapable of combining effica- 
ciously with tannin, and the pores of the skin are so 
impregnated with lime that the tanning principle cannot 
operate freely and penetrate to the heart of the skin. 

2. When catechu is used, the leather produced is very 
permeable to water, light and spongy and of a dark red 
color. This state is produced by catechuic acid and 
some other extractive matters which are found in the 
catechu. 

3. When we macerate tan or other similar substances, 
such as divi-divi and sumach, with water for tanning, 
those substances by the action of the oxygen of the air 
produce gallic acid, which is a solvent of gelatine, 
and consequently noxious in the tanning, at the same 
time that it causes an expansion in the pores of the hide, 
and as it does not help in the combination of the tannin 
with the gelatine, the leather remains spongy, porous, and 
of an inferior quality. 

The principal object of M. Turnbull has been to re- 
move these inconveniences and difficulties and to pro- 
duce a rapid and efficacious combination of the gelatine 
of the skin with the tanning matter. 

The first point consists in removing the lime contained 
in the skins, or to use other means of raising sugar and 
saccharated matters contained in vegetable substances, 
having the property to combine with lime and to dissolve 
it. It is the same with pyroligneous acid or wood vinegar, 
consequently to extract the lime contained in skins pre- 
pare a solution consisting of 14 pounds of sawdust, 4 
pounds of raw sugar and 300 quarts of water. It" can 
also be composed of sawdust alone in the proportion of 



turnbull's process. 449 

28 pounds for the same quantity of water. The solu- 
tions are made either cold or warm, but always used 
cold; macerate in the skins for two or three days, which 
is sufficient to dissolve all the lime. 

To raise the skins without lime Mr. Turnbull dips 
them first in a solution of sugar or any saccharine 
matter; second, in a solution of common salt. ' By the 
first means sugar dilates the gelatine, and renders the 
raising easier. In the second the salt contracts the epi- 
dermis without acting on the gelatine, separates it from 
the true skin, so that the hair can be taken ofi" without 
producing any alteration in the gelatinous matter of the 
skin. The solution of sugar is thus formed : 14 lbs. of 
raw sugar or molasses for 112 gals, of water kept at a 
temperature between 50° and 77°. The skins are left in 
from five to ten days. The solution of salt is formed 
with 14 lbs. of salt in 112 gals, of water kept at a tem- 
perature between 68° and 86°. 

Turnbull's process to separate catechuic acid from 
the other principles contained in catechu, from tannic 
acid, and to avoid the formation of gallic and ellagic acid 
when gall, oak bark, divi-divi, etc., are used, is the 
following : — 

Reduce the catechu to a fine powder, treat that powder 
by cold water until no more is dissolved. Pour the cold 
solution into a vat or cylinder provided with a metallic 
tissue or cotton cloth. The catechuic acid insoluble in 
cold water stays on the filter and the solution of tannin 
is freed from these matters. 

To prevent the formation of gallic and ellagic acid he 
reduces the material into powder and prevents the contact 
of the air during the tanning, as we shall see hereafter. 

The skins thus prepared are well washed and tanned 
by two different processes. First, by the application of 
29 



450 ' TANNING. 

a certain physical force different from capillary attrac- 
tion and hydrostatic pressure. Second, in vats com- 
municating one with the other, as we shall explain 
hereafter, so as to maintain a constant agitation and circu- 
lation in the tanning matter, until the skins are tanned. 

The physical force that Mr. TurnbuU proposed to 
apply to the tanning of the skins is that one which pro- 
duces the eiidosmose and exosmose. For this purpose he 
takes the skins to form bags in which he introduces the 
tan in the proportion of 2 lbs. for every pound of damp 
leather. He shuts the bags in which he keeps a small 
aperture by which he pours in cold or warm water, 
then hermetically closes the hole. These bags are then 
introduced in closed wooden vats filled with a purified 
.solution of catechu. In this manner during the operation 
the solution is not attacked by the air, and the formation 
of gallic acid is thus avoided. Thus, to increase the 
densitj^ of the vats, he adds 14 lbs. of sugar for every 112 
gals, of liquor. 

The two liquors thus prepared and used, the effects of 
endosmose and exosmose are produced, and tannic acid 
passes rapidly through the skins until they are perfectly 
tanned. Draw the bags from time to time, and when 
they are partly emptied by the filtration they are filled 
ao^ain with water. 

During the tanning it is necessary to keep the density 
of the liquor of the vats by adding to it sugar from time 
to time. Instead of catechu you can use Valonia and 
€ven tan in the proportion of a half of the first. For the 
cvxtechu it must be introduced in the bags only purified 
and in solution in the proportion of 2 lbs. of catechu 
equal to 8 lbs. of tan for 10 lbs. of skins. 

i'ou can dispose a series of vats, closed so as to main- 
tain \a constant movement and circulation. For this 



turnbull's process. 451 

purpose fill these vats with a liquor composed as above, 
leaving in them a space sufficient to introduce the skins 
one on another, then close these vats so as to exclude 
the air, and finish by filling with the liquor, then esta- 
blish a forcing pump, which by means of an aspiration 
pipe goes to the bottom of each vat. Draw the tan- 
ning liquor, raise it and pour it in another distribution 
pipe, which by means of little pipes forces it to the upper 
part of the vats. 

When you operate on catechu to separate the tannic 
acid from the catechuic ncid, and other useless matters, 
the deposit which forms in the vat is at least five per 
cent, in weight of the catechu put in dissolution. This 
deposit can be purified, and rendered proper for tan- 
ning. Deposit it in an oven, or in an evaporating vessel, 
and heat it at 161°, then expose to the air, and stir it until 
it takes the color of the powdered catechu. This matter, 
dissolved and filtered, contains as near as much tannin 
as the catechu dissolved in the first place. 

The skins from which the lime has been separated, or 
those treated without lime, can be tanned in the usual 
way with catechu purified as above, or with other tan- 
ning substances. The leather produced by this process 
is heavier, and of better quality than by the old method. 

Later, Mr. Turnbull gives the following details.'^ 

" The economy obtained by my process is immense, 
and I will prove it in a few words. 

" Thus, 100 lbs. of hide in the green state furnish 
only from 45 to 50 lbs. of tanned leather, requiring 
300 lbs. of oak bark, and the operation lasts 18 
months. By my method, 14 days are sufficient. For 
the same weight of skin, I use only 100 lbs. of oak bark, 
and after the operation I obtain 60 lbs. of leather; while 

* Comptes Rendus. Acad, des Sciences, Janvier 12, 1846. 



452 TANNING. 

by the old method the tanner can prepare only one 
skin, I can prepare 39. 

" The tanning of calf-skin requires by the usual method 
from five to six months ; from two to four days are suffi- 
cient by my process. 

"At last, if the tanner will use only the first part of 
my process, that is the saccharated solution, destined to 
prevent the action of the lime, he reduces the operation 
for calf-skins from six months to ten days." 



CHAPTER XCIII. 

S. SNYDER'S PROCESS. 

Every one knows how important it is to saturate the 
hides with tannin as quickly as possible after they have 
been prepared to be put into the tanning vats, but till 
now this saturation has been done so slowly that it is 
often the cause of losses difficult to avoid. We will 
describe now a process which enables us to attain this 
object quickly, and which we have no doubt can be used 
in practice. 

Mr. Snyder takes the hides after the working in the 
river, when they are very soft and flexible, and he acu- 
punctures them on the entire surface, that is, he perforates 
them with an instrument presenting a surface armed 
with fine steel needles. A man can prepare from 30 to 
40 hides daily, but the operation can be rendered more 
economical and rapid with the help of a machine. For 
.some kinds of leather you must acupuncture on the grain 
side, while in some others on the flesh side. 

Every one admits that a hide thus treated will be 
tanned much quicker than one which is not ; but this 



Snyder's process. 45*3 

idea to perforate thus an article, the object of which is 
to be water-proof, seems a paradox. But its author re- 
marks that it is when the hide is in its greatest state of 
softness that the operation is performed, and he affirms 
by experiment that in this state the skin is not altered. 
As a proof he presented some skins, perforated and 
tanned, in which the puncture was not perceived above 
the grain. Indeed the soft skin contracts by the desic- 
cation, and the tannin with which it is impregnated 
gives it back its thickness and its primitive firmness, in 
obliterating all the pores and perforations. 

A better leather can be prepared by this method than 
by the other, for the following reasons : — 

1. Because it accelerates the tanning so as to require 
a more frequent renewal of the liquor, which has no 
time to become acid ; for it is a known fact that a tan 
liquor becomes acid in ten days, and in the ordinary 
process the leather is left sometimes 6 or 8 weeks in the 
same liquor, which consequently becomes sour. He sur- 
mounts this difficulty by exposing a more considerable 
surface of fibres to the immediate action of the tannin, 
which causes a quicker combination, requires a more 
frequent renewal of the liquor than by passing it through 
a" bed of powder, and insures its being fresh and sweet. 

2. Because by bringing the tannin into immediate 
contact with the interior fibres a chemical change is pro- 
duced at the same time as that on the exterior surfaces, 
which need not be over-tanned. This exterior surface is 
rendered hard and brittle as usual, by continuing the 
action until the tannin has penetrated inside. 

According to the author he can tan in half the time 
of the ordinary process, and consequently save much 
cost and labor. If j^ou want to operate quicker, hy- 
drostatic pressure can be applied, which does very well 



454 TANNING. 

with the acupuncturej and it requires less pressure than 
that usually employed, which often weakens the fibres 
of the skin. 



CHAPTER XCIY, 



H. HIBBARD'S PROCESS. 



This process unites in a high degree the advantages 
of economy, time, and labor. It is applicable to all kinds 
of skins, and produces a solid and durable leather. The 
process is described by his author as consisting : — 

'''First. In the use of a composition of lime, wood, 
ashes, and salt, the object of which is to remove hair and 
wool, also for liming instead of using lime alone. We 
have described the objections to the use of lime and 
ashes separately, but when combined in proper propor- 
tions the salt modifies the action of the alkalies and 
protects the skin from their caustic properties, so that the 
process of unh airing is rendered more expeditious and 
safe than by the old process. The texture of the skin 
is uninjured and the leather is much stronger. >^ 

" Second. In the use of a composition of salt, sulphuric 
acid, and sumach, oak, hemlock, or any other tanning 
material. The salt, sulphuric acid, and tannin being 
mixed together in water in certain proportions, a portion 
of the salt is decomposed by the acid to form sulphate 
of soda, and set at liberty hydrochloric acid, which is 
redissolved by water, acts on the skins, opens the pores, 
and prepares them for the tannin, which being present in 
the mixture, readily unites with the principles of the 
skin and forms leather more expeditiously than by the 
old method. 



HIBBARD 3 PROCESS. 



455 



2 

3 pints. 



Preparation of the Skins. 
" Prepare the following composition : — 

Quicklime (freshly slacked) . . . ^ bushd. 
Wood ashes ..... 
Salt 

" To remove the hair mix the above composition with 
water sufficient to make a thick paste, apply it to the 
flesh side of the hides, fold the skins and keep them at 
a temperature of summer heat. In a few hours they 
are ready to pull. 

" For the liming process I use the same composition, 
mixed with a sufficiency of water in a vat to immerse 
the number of skins proposed to be limed. One bushel 
is equivalent to one bushel of lime alone. The liming 
is done at the temperature of 60°. 

Composition for Tanning. 

" For six dozen of full sized sheep, deer, goat, or simi- 
lar skins, prepare the following composition : — 

Salt 18 lbs. 



Sulphuric acid 

Sumach or quercitron bark 

Hydrochloric acid 

Dried clover. 

Water .... 



2 " 
36 " 

2 ounces. 
18 lbs. 
125 gals. 

" Exhaust the sumach by water, add the salt, enough 
to insure perfect solution. Add then the acids and 
incorporate by stirring." 



456 TANNING. 



CHAPTER XCV. 

HEMLOCK TANNING. 

The hemlock forests of New York and Northern Penn- 
sylvania are very extensive, and the readiness and cheap- 
ness with which the bark may be obtained have brought 
it into general use, in those Spates, as tanning material. 
It may be employed alone, or in combination with oak 
bark, 

In order to produce heavy weights the hides should 
not be reduced too low in the beam house, and should 
be tanned quickly with strong, good liquors, principally 
in the last stages of the operation. Nothing is more 
injurious to green hides than to leave them too long in 
weak ooze; they become too much reduced, grow soft, 
flat, and flabby; lose a portion of their gelatine, and 
refuse to plump up. 

The soaking and sweating are made in the ordinary 
manner, and the following table shows the time employed 
for these operations at different temperatures : — 

Soaking. 
Suenos-Ayres hides . 
Garthagena " 

Sweating. 
Buenos-Ayres *' 
Garthagena " 

Soaked hides do not require more than two-thirds of 
the time to soak, but rather longer to sweat. 

After these operations are done, pass to the liandling, 
which is performed two or three times a day in a weak 



40O. 


50O, 


60O. 


70O. 


Days. 


Days. 


Days. 


Days. 


10 to 12 


8 to 12 


6 to 8 


3 to 6 


8 to 12 


T to 9 


5 to 7 


2 to 3 


15 to 20 


12 to 16 


8 to 12 


2 to 3 


15 to 20 


10 to 15 


6 to 8 


2 to 3 



HEMLOCK TANNING. 45 T 

ooze until the grain i.s colored. New liquors, or mixtures 
uf new and old are preferable for dry hides, old liquors 
for slaughtered. They are then, after a fortnight, laid 
away in bark, and changed once in two or four weeks 
until tanned. Much care and judgment are necessary 
in proportioning the continually increasing strength of 
the liquors to the requirements of the leather in the 
different stages of the process. The liquors should also 
be kept as cool as possible, within certain limits, but 
ought never to exceed a temperature of 80°. Too high 
a heat, with a liquor too strongly charged with the 
tanning principle, is injurious to the life and color of the 
leather. If too strong a solution is injurious, the use 
of a too weak one must be avoided. Hides treated with 
liquors below the proper strength become relaxed in 
their texture, and lose a portion of their gelatine. The 
leather loses in weight, and is much more porous. The 
greatest strength of liquor used for handling must mark 
16° by the barkometer; and that employed in laying 
away must mark at its greatest strength from 30 to 45°. 

After the leather has been thoroughly tanned and 
rinsed, or scrubbed by a brush machine or broom, it will 
tend very much to improve its color and pliability to 
stack it up in piles and allow it to sweat until it becomes 
a little slippery from a kind of mucus that collects upon 
its surface. A little oil added at this stage of the process 
has been found very useful. 

The average time of tanning by hemlock amounts to 
five months twenty-seven days. The English tanners 
employ from eight to ten months. 

We need not dwell much longer on this process, 
which is the same as with oak bark. The leather it pro- 
duces is good, and easily recognized by its red color. 

To tan sole-leather with hemlock takes from four to 



458 TANNING. 

six months, according to the strength of the liquor and 
number of sides in the vats; and the quicker tanned 
the better. The weight of the liides if heavy requires 
more time than if comparatively light. If the hides are 
fresh, they are capable of being properly softened ; and if 
so, the process of tanning may be completed sooner than 
in the case of old and hard hides that cannot be softened 
so easily. If the hides have sufficient room in the vats 
they will tan much faster. As the tanning advances 
the liquor should be renewed seasonably, and its strength 
increased in a ratio proportionate to each stage of tanning. 

Process of Tamiing as Performed at the ShaJcer Tannery 
of New LehanoT}, N. Y. 

"We are indebted to M. Fred. Sizer, the Shaker tanner, 
for the following account of the process of tanning as 
performed in that village. All those who are acquainted 
with the products of that society will know the value 
of this process, which we, without hesitation, recommend 
as purely practical. We give it in the words of its 
author : — 

" I take a pack of calf-skins — say one hundred dry 
skins — and put them in a water vat to soak ; after they 
have soaked two or three days, I take them out and mill 
them (a wheel is best for milling hides)'. I then beam 
them on the flesh side, removing all the lean meat and 
grease from the skin, stretching them out well with the 
beaming knife, and put them into a vat of clean water 
until they are soft enough to go in the lime. .They 
must be as soft as they were when they came off the 
animal, or as near that as you can get them. If the 
hides are not soft before going in the lime, they never 
can be, and the leather will always be hard. 

" Fresh hides that come directly from the butcher are 



HEMLOCK TANNING. 459 

put in the water a day or two; change the water once ; 
beam on the flesh side to get the meat and grease off, 
then they are ready for the lime. 

" I make my lime in a vat 8 feet long, 4 wide, and 4 
deep. One bushel of slaked lime and 2 gallons soft soap, 
put in the vat two-thirds full of water, will make a lime 
sufficient for 100 calf-skins, or 50 sides of upper leather. 
The hides should be hauled out every other day, while 
in the lime, to air and change their position; then stir 
the lime well before they are put back. 

" The lime needs strengthening every time a new 
pack is put in, by adding say half bushel lime and two 
or three quarts soap, I lime my calf-skins and upper 
leather hides until the hair comes off easily (but sole 
leather should be limed as little as possible and get the 
hair off) ; then unhair them, wash them out in the mill, 
beam them on the flesh side, trim off the pates and 
shanks, and put them in the bate. 

" I put 5 or 6 bushels hen dung into a vat of the same 
dimensions of that used for the lime, and fill two-thirds 
full of water, and let it stand two or three days to fer- 
ment. I let my skins remain in the bate two or three 
days in warm weather, and longer in cold ; haul them 
two or three times while in the bate, and work them 
twice on the grain with a common worker on the tan- 
ners' beam ; mill them before working the last time ; 
then beam them, and they are ready for the tan vats. 

" I make a liquor of moderate strength to handle them 
in, put them in this liquor, and stir them with pole a 
while ; then I handle them up smooth on a box or rack 
three or four times in the course of the day; let them 
remain in this until the next morning, then change the 
liquor, giving them about the same strength they had 
the first time ; handle them two or three times a day in 



460 TANNING. 

this liquor, and when the liquor is exhausted change 
again and handle less as the skins get colored and the 
grain set. I make my liquors of hemlock bark, ground 
and put in leeches, and pump in exhausted liquor. The 
first strength of my leeches I draw off into my sole leather 
vats ; I draw off my leeches two or three times before 
taking it for my upper leather and calf-skins, and these 
I keep in mild, sweet liquors through the whole tanning 
process. 

" I handle my hides and calf-skins through until 
tanned, changing the liquors as they get exhausted. 
After they get well along, I handle' three times a week. 
They will do to lay longer, but will tan faster to handle 
often. 

" "When my calf-skins have been in the tan two or 
three weeks, 1 shave down the necks ; and after my 
upper leather has been in four or five weeks, I shave it 
down to a proper thickness. 

" In my experience in tanning, which has extended 
through forty-two years, and I have used both hemlock 
and oak bark, I find that mild, sweet liquors are far the 
best for tanning all kinds of upper leather. The hide 
in the raw state is tougher than when tanned, and that 
toughness ought to be preserved as much as possible and 
make good pliable leather, and the slow process of tan- 
ning wdth mild liquors will do it. Strong liquors have 
a tendency to make the leather hard and liable to crack. 

" The hides for upper leather should not be tanned 
any more than thoroughly through; if tanned longer 
than this, it has the same effect upon them as strong 
liquor. But the longer sole leather is tanned the better. 

" When I think my leather is nearly struck through 
I try it by cutting into the thickest edge, and when 
tanned through take it up and scour it out in the wheel 



halvorson's process. 461 

to cleanse it from the tan and soften the grain ; then 
take them to the currying shop, and the calf-skins I 
skive and upper smooth down with the currying knife; 
then put them in a tub of water and scour them on the 
table with a brush, stone, and slicker ; dry them a little 
to temper them, and then put them on the table and set 
them on the grain side to work the grain out smooth. 
After that apply some thin stuffing made of oil and 
tallow ; then turn them over, the flesh side up, and set 
them out with an iron slicker ; then apply the stuffing 
more plentifully, made thicker with more tallow; then 
hang them on sticks and dry them, and then pack them 
down in a pile and let them stay two weeks. I then 
take them and rub off what stuffing does not strike in, 
and whiten them with a currying knife or slicker. 

" I commonly whiten my calf-skins and kips with a 
slicker, and finish in the French style. 

" Since the French degras has come into use I have 
used it for calf-skins and kips. I have also, for some 
time, used tansy in my liquors. There is an acid in tan 
that injures the leather which tansy neutralizes, and 
keeps the liquor sweet." 



CHAPTER XC7I. 

HALVOESON'S PROCESS FOR RENDERING HIDES HARD 
AND TRANSPARENT. 

This method, patented by H. Halvorson, is thus 
described : — 

" I take the raw hide and submit it to the sweating 
operation sufficiently to remove the hair, or I immerse 
the hide in a solution of lime or alkali proper to remove 
the hair. I then submit it to the action of a boiling 



462 TANNING. 

bath of any powerful astringent and alkaline, or any 
other substance sufficient to remove the fatty matter and 
make it thicker. 

" So far as my experience goes I find sulphuric acid, 
salts of tartar, and alum, dissolved in water, to answer 
a good purpose. I keep the hide in the boiling solution, 
stirring frequently, and handling the hides while under 
the influence of the bath, in order to cause the liquid to 
penetrate it. 

" After having fulled it to the desired thickness I rin«e 
it in warm and clear water and dry it. The hide is 
opaque, and is very easily affected by the atmospheric 
changes. In order to render it semi-transparent and 
capable of resisting the influence of atmospheric changes 
I immerse it in a vessel full of boiling drying oil, and keep 
it in until a white or yellowish scale begins to form on 
its surface, then I remove the hide from the fire. While 
hot it can be pressed or moulded into various shapes. 
When cold it is converted into a substance resembling 
horn or tortoise shell, and may be worked like them or 
ivory. ' 

" If the hide be designed for embossed works, it is ad- 
visable to remove it from the oil as soon as it acquires 
the desired transparency and softness. 

" After being thus prepared it can be moulded. During 
the last portions of the process the material may be 
stained by adding to it any material proper to produce 
any desired color. 

'• Where it may not be required to thicken a hide to 
its greatest extent of capacity the use of an astringent 
solution may be dispensed with, it being only necessary 
in such cases to employ the alkaline solution, and after- 
wards expose the skin to the action of boihng oil as 
above described." 



TAWING. 463 



CHAPTER XCVII 



TAWING. 



This process is applicable to the manufacture of soft 
leather for gloves and furrier's uses, as skins may be 
subjected to its action even in their hair state. It is 
sometimes called alumed leatlier, because a salt of alumina 
is the basis of the process. The skins usually submitted 
to this treatment are sheep, lamb, kid, and other light 
skins. 

Kid Leather. 

.The first operation is to soak the skins well in running 
water and to break them upon the beam by working on 
the flesh side with the back of the fleshing knife. Then 
they must be immediately dried to prevent putrefaction, 
which will render them spotted and tender. Dry skins 
require a soaking of one or two days. 

Then rub the flesh side with a cold milk of lime, place 
them back to back in pairs with the back outwards, stack 
them in piles, and leave them several days until the hair 
gives readily. Rinse them in running water, to remove 
the lime, and fleece themj this operation consists in 
plucking out the hair with spri;ig tweezers, and smooth- 
ing by rubbing with a whetstone or rolling pin. Cleanse, 
and soak again in the lime vat, whence, after being re- 
moved, they are transferred to an old or weaker vat, and 
there remain for a fortnight or more, being careful to 
take them out and drain them frequently. They are 
now ready for the hrannbig. For this purpose they un- 
dergo a steeping for 10 or 15 days in a fermenting mix- 



4 

464 - ^ TANNING. 

ture, or drench of 40 galls, of bran .and 20 galls, of 
water. As soon as the skins sink in water they are 
sufficiently raised ; this operation requires two days in 
summer and four days in winter, and great care is neces- 
sary to observe when they reach that stage, which may 
• be attained earlier by frequently turning the skins. 

When taken from this liquor they are put in the white 
hath, composed, for 100 skins, of a boiling solution of 10 
to 12 lbs. of alum in 12 galls, of water, to which you 
add, in summer, 2 J lbs. of common salt, and in winter 
3 lbs. Divide the skins into four equal parcels, and pass 
each parcel separately and successively in this bath, and 
then immerse the whole together for ten minutes. 

Make a paste by gradually adding, during a constant 
stirring, jQrstly, 15 lbs. of wheat flour to the alum bath 
gently heated, and subsequehtly the yelks of fifty eggs, 
and then incorporating the whole thoroughly. The skins, 
after being passed in this paste singly, are transferred to 
it in bulk and left for a day. 

This paste has an emulsive action, softens and whitens 
the skins, counteracts the hardening influence of after 
exposure to the air, and tendency to brittleness. 

After this operation stretch the skins upon poles in a 
drying loft and there leave for a week or more, as may be 
necessary. They are then ready to be worked upon the 
softening iron to stretch them, reduce uneveness, and 
develop whiteness. For .this purpose they are soaked 
in water for 5 or 6 minutes, and then spread and soft- 
ened by the process of staking. 

Next they are stretched on hooks, dried, and worked 
on the stretching iron, but some tanners, after the skins 
come from the smoothing iron, spread them upon the 
beam, with a clean undressed skin beneath, and work 
them with the fleshing knife. 



TAWING. 



465 



Sometimes the prepared skin is polished by being 
rubbed with pumice. The lustre and finishing stroke 
are given with a smooth flat-iron carefully heated. 

In some places the process is slightly modified. For 
example, by the use of a large barrel churn, or round- 
about, which receives both the skin and the alum bath. 
Rapid rotation of the apparatus promotes constant 
contact of the skins and tanning material, and accele- 
rates the operation. The tanned skins, after coming 
from the paste, and being washed and dried, are sub- 
jected to the staking, which consists in the use of a semi- 
circular iron plate, fixed perpendicularly, with its round 
edge uppermost, to the top of a wooden stake about thirty 
inches high. The workman, holding the skin distended 
by both hands, draws it forcibly, and in every direction, 

Fig. 116. 




over the blunt edge of this tool, and thus imparts soft- 
ness and smoothness to it. 

Tawed leather is raw skin combined with chloride of 
aluminum. The alum is decomposed. Its aluminum 
30 



466 TANNING. 

combines with the chlorine of the chloride of sodium 
(salt), and the sulphuric acid of the alum forms a double 
sulphate of potash and soda, as represented in the follow- 
ing reaction : — 

KO.SOg, AlA 3(803)+ 301 Na = KO SO3 + 3NaO SO3 + Ole Al^ 

Chloride of Sulphate of Sulphate of Chloride of 
Alum. Sodium. Potash. Soda. Aluminum. 

Imitation Kid. 

Imitation kid is made from lamb-skins. Lime is not 
used in order to remove the wool without injury. Steep 
the skins in water, and break them on the flesh side; 
suspend them in a subterranean vault twelve feet square, 
protected as much as possible from atmospheric changes, 
so that the temperature stays the same all the year 
round. An incipient putrefaction is promoted, the roots 
of the wool are loosened, and it is readily plucked from 
the pelt ; and when this state is reached, which takes 
from five to seven days, the skins are removed, to avoid 
injury. 

The skins are then slimed ; that is, are scraped on the 
flesh side, stripped of wool, and steeped for a week in 
lime water, fleshed on the beam, drenched for some days 
in a fermenting bran-bath, and treated w^ith alum and 
salt in the same manner as true kid. Dyeing, softening, 
and polishing complete the preparation of the leather. 



METHOD OF TANNING SMALL LAMB-SKINS. 467 



CHAPTER XCVIII. 

THE BEST METHOD OP TANNING SMALL LAMB -SKINS, 
CALLED CHAMOIS, AND ESPECIALLY WHITE PELTRY 
FOR FURRIERS. 

M. A. Bruggemann describes a process, the principal 
result of which is, that the skins retain their fur, and 
that they remain dazzHngiy white; further, that they 
become strong and exceedingly soft, which is best attain- 
able in the following manner: — 

The skins should be allowed to soak about eighteen 
hours in water, but not longer, or the fur will become 
loosened and the skin be rendered useless as peltry. 
Then they should be taken out of the water, and rinsed 
in running water. After the water has been drained 
off, or pressed out, the skins should be laid separately, 
with the fur sides uppermost, on a table or suitable 
board, and then carded, one after another, with the 
coarsest description of wool comb, especial attention 
being paid to the dirtiest spots, and great care taken that 
the fur may not be injured. The dirtiest spots should 
be rubbed with soap, and, that it may thoroughly take 
effect, the soaked skins should be allowed to remain un- 
touched one or two hours. When there are large lots 
to be dressed together, the work goes on without inter- 
ruption on this account, the skins first soaped being the 
first ready for the next state of the process. After the 
soa,ping, arid after it has been allowed the necessary time 
to work in, the skins require to be once more carded, 
especially upon the soaped places. Then will be seen 
which portion of the pelt stands in need of a more 



468 TANNING. 

further soaping; this should be done at once, and the 
skins allowed to lie a short time longer, that the soap 
may take effect; then they should be carded and washed 
clean. 

Those skins found to be quite clean should be washed 
or rinsed in running water, which ends this part of the 
process. The washing out of the pelts, like all the pre- 
ceding operations, requires great care in order to make 
them of uniform cleanliness. The skin should be held 
by one of the hind legs, that the other leg and the entire 
hinder part of the skin may be turned in washing evenly 
right and left, so that the other portions of the skin may 
continue in level motion on the water. If this particu- 
lar, however insignificant it may appear, be not attended 
to, clean pelts cannot be obtained without much loss of 
time. After the skins are cleaned on the fur side, and 
the water drained off or squeezed out of them as much 
as possible, the flesh or fibrous part of the skin is re-- 
moved by drawing it over a stationary iron instrument 
contrived for the purpose. This fieshing operation is also 
intended to render the skin pliant, and is of importance 
to its ultimate softness. After fleshing, the skins should 
be laid singly on a board, with the fleshy side uppermost, 
and carefully examined, heads, legs, tails, etc. Then take 
barley groats, or, in the absence of this, a mixture made 
of 3 parts wheat bran and 2 parts rye flour, which will 
answer the same purpose, and strew a layer of barley 
groats or the other mixture over each skin, covering the 
surface uniformly. Then roll each skin together, with 
the wool or fur side, of course, outward, with the legs, 
head, and edges well tucked in, and pack them thus 
rolled one by one in a water-tight vat. When the vat 
is tolerably full, or the stock of skins exhausted, pour 
salt water, that will bear an egg, upon the skins, and 



METHOD OF COLORING "WHITE TAWED LEATHER. 469 

sufficient to cover them entirely. They should be left 
to remain there about twenty-four hours. It must be 
noted that the vat containing the skins should stand in 
a cellar, or in some other cool place, where it can be 
protected against frost. After the specified time the 
skins should be carefully unrolled, so that the bestrewn 
parts be as little disarranged as possible ; then lay them 
with the fur side inwards, by twos flat together, the head 
of one being upon the tail of the other, and pack them 
thus flatly in another vat. Care must be taken not to 
press out the moisture remaining in the skins, as their 
peculiar nourishment or fermentation would thus be re- 
moved. During fourteen days, or ten will be sufficient 
at a high temperature, the skins must be daily re-packed 
and changed to another vat, so that all their parts may 
absorb the liquor uniformly. If this is not carefully 
attended to daily, the skins will certainly be speckled, and 
possibly entirely ruined. After the time mentioned, the 
skins should be taken out of the vat, drained, and the 
moisture got rid of by pressing or squeezing ; then they 
are dried, and the dressing process begins. 



CHAPTER XCIX. 

NEW METHOD OF COLORING WHITE TAWED LEATHER. 

Pelts, to be well colored, should be made perfectly 
smooth on the flesh side before being cleaned, this is ac- 
complished by reducing the thickness of the skin on that 
side by means of the flesher and then making it perfectly 
even. In order to facilitate this operation, and that the 
flesher may take better hold of the portion which it is" 
desired to remove, the side of the pelt operated upon 



470 TANNING. 

ought to be well rubbed in with thin chalk paste. After 
the skin has been properly smoothed it is cleaned, wrung 
out, dried, and stretched out. The next operation is to 
place it on a tin or zinc table, with the flesh side outward, 
to stretch it tightly, and then to apply to its surface the 
desired coloring matter by means of a soft brush with 
long hair. After this, and while the pelt is still damp, 
it should be well rubbed in with pumice stone, being for 
that purpose stretched out on a frame. The workman 
performing this part of the operation holds with his left 
hand the frame, on which the skin is extended, and 
rubs it downwards with the pumice stone which he 
presses as hard as he can. The skin should be thus 
pumiced from the tail to the head, then again from the 
head to the tail, and then from flank to flank, the latter 
if the condition of the skin requires it. After pumicing 
the pelts are dried on wooden platforms or scaffoldings, 
provided with hooks, in a room where they can be so 
hung as not to touch each other. The dried skins are 
again placed on the table as before, receive the second 
coating of color, and are again carried to the scaffolding 
to dry. This operation is repeated a third time, and if 
the color answer the expectation the labor is completed; 
if it should not prove sufficiently dark, a fourth coating 
will bring it to the desired shade, but this is seldom re- 
quired, except for skins intended for the best description 
of gloves. 

This method is called the Parisian method; it differs 
from the one called the Grenoble method. In the former 
the skins are colored three or four times, while in the 
latter the operation is performed but once. The disad- 
vantage of the Parisian method is that the repeated re- 
moval of the skin from the table to the scaffolding and 
back again subjects them to the danger of being soiled ; 



QUICK TANNING. 471 

this, however, can be avoided by careful handling, and 
the disadvantage is counterbalanced not only by the color 
being more uniform and. true, but by the suppleness 
which the skin acquires by this operation. 



CHAPTER C. 

QUICK TANNING. 

Tanners and leather dealers are often charged with 
being opposed to innovations, and slow in adopting or 
introducing improvements. This, to a certain extent, 
may be true, but we can hardly believe that tanners, as 
a class, are more indifferent than others to their own 
interests. It is undoubtedly true that the various steps 
in the process of tanning have been, and still are, to a 
large portion of American tanners, merely mechanical. 
They do not understand the principles, and know results 
only as a matter of experience. This want of knowledge 
has left a large field for fraud and imposition, which has 
not been unimproved. There is hardly a tanner in the 
country, who has not, some time or other, paid dearly 
for some alleged important information, new invention, 
patent process, etc., which have proved worthless, and 
smarting under the failure of some impostor's theory, is 
it any wonder that the tanners became jealous and 
backward in adopting new processes. We believe, if it 
be fully proved to the tanners that an invention is an 
actual improvement, that there is no class of men more 
willing to receive, use, and pay for, such inventions. 
They are a class more sinned against than sinning. 

Many tanners maintain that there is no advantage 
whatever in keeping leather in process after the gelatine 



472 TANNING. 

and tannin have united. There is much diversity of 
opinion upon the length of time necessary or advanta- 
geous, to keep leather in the tanning liquor, but it 
doubtless depends very much upon the preparation of 
the hide. Tanners generally do not pay proper attention 
to the early steps — those of unhairing and raising. Is 
there any necessity that time be given after the tannin 
and gelatine have united, for leather to consolidate and 
grow ? Is there any gain in weight, if even made more 
durable by such delay ? What length of time is it neces- 
sary to let hides tan which are limed or sweated in the 
common method ? These are questions often asked, and 
on which the views of practical men are desired. 

The fact is, that when the tannin and gelatine are 
completely united, the process of the formation of leather 
is exhausted. But in the ordinary manufacture it is 
never the case that the hide has received all the tannin 
of which it is capable, and therefore an extension of time 
is followed by an increase of weight. If all the gelatine 
of the hide could be exposed at the same moment to the 
action of the tannin, the process would be instantaneous, 
and this is what the patented processes profess to facili- 
tate. There is no doubt that improvements in this 
direction are feasible, and that a considerable time is 
now actually gained over the old periods of manufacture 
without any injurj^ to the leather. But no improvement 
has yet so facilitated the quick production of leather, 
that a material gain in weight may not be secured by a 
protracted stay in the vats, while attempts of this kind 
by the use of deleterious substances have often resulted 
in rotting the fibre of the hide. 

Has there ever been any leather tanned in two, three, 
or six months, by any patented process, which has 
claimed to be equal to the English band leather ; and 



QUICK TANNING. 473 

what gives the great superiority to this class of leather 
if not the length of time it is in tan? It is well known 
that the oak tanners of Pennsylvania and Maryland are 
about twice as long in tanning leather as the hemlock 
tanners. May it not be this length of time in tanning 
which gives the general superiority to oak leather? It 
is a general complaint that leather tanned by quick 
processes is wanting in solidity and strength. It is 
porous, easily filled with water, and wanting in durable 
qualities. A few years since a tanner in Pennsylvania 
had several hundred sides of leather in vats tanned the 
usual time. A part of this leather had been dried out 
and sent to market, when an event occurred that entirely 
stopped the working of the yard for six months, and 
the residue of the leather remained undisturbed in the 
vats. This was finally sent to market, and on compari- 
son with the stock sent six months earlier, was found to 
be a much superior article, besides having gained from 
6 to 8 per cent, in weight. We do not mention this as 
an example for imitation, but simply to show that tan- 
ners, under the common system, frequently hurry out 
their leather before they realize the full gain. 

We give below a few of the quick tanning processes. 
We could have given more, but in reality they are all 
much the same; they vary only in proportions. 

S. Dunseith's Process. — The skin, with or without hair, 
is submitted to a tan liquor composed of one gallon of 
strong decoction of Anthemis Gotula. To this decoction 
he adds — 

Catechu ^ lb. 



Alum i " 

Common salt . . . . . ^ " 
Stir well. 

Then the hides are immersed in that solution for a 



474 



TANNING. 



time more or less long, from three hours to twenty days, 
stirring and handling frequently. If desired, terra ja- 
ponica may be used without the anthemis, in the following 
proportions : — 

Terra japonica .... 12 lbs. 
Water 15 gals. 

To which are added — 



Alum 
Salt 



If lbs. 



But the first formula is better. 

When the skins are tanned without removing the 
hair, they are soaked in water until perfectly soft and 
pliable, and then they are worked on the flesh side. 
When the skins are prepared in the lime vat instead of 
the bat vat (hen-dung), for neutralizing the lime the fol- 
lowing composition is used, and the skins are soaked in — 



Water 

Sulphuric acid 
Salt 

Wheat bran 
Stir and mix well. 



30 gals. 

1 lb. 

6 lbs. 

1 bushel. 



Prepare the skins on the beam in the usual manner, 
and they will be ready for the tanning liquor. 

M. D. Kennedy s Process. — In this process the author 
uses the divi-divi, catechu, oak. He combines the tannin 
with the sulphates of soda, magnesia, alumina, carbon- 
ate and borate of soda. The liquor of the vats is pre- 
pared with — 

Tanning material .... 30 lbs. 

Sulphate of soda .... 8 " 

Sulphate of magnesia ... 4 " 

Alum 1 " 

Carbonate of soda . . . . 2 " 

Borate of soda .... 1 " 

Ammonia 1 " 



QUICK TANNING. 



475 



/. L. WeJls Process. — The composition used by the 
author is the following : — 

Soft water . . . . . 128 gals. 



Catechu 
American sumach 



100 lbs. 
150 " 



J. Cochran s Process. — The hair is removed from the 
hides by any of the known processes, after which they 
are handled from two to four days in the following com- 
pound or solution : — 
Water 



Terra japonica . 


8 lbs. 


Salt 


16 " 


Elder extract 


8 ounces 


Saltpetre . 


2 lbs. 


Alum 


1 lb. 


Aloes 


1 "! 


Opium 


1 ounce. 



This composition is too costly to employ in the usual 
practice, and we doubt its efficacy. 

W. R. Webster s Process. — The hair is removed by 

the usual process, and the hides are passed through the 

bate, and then are saturated by passing them in the 

following solution : — 

Water 100 gals. 

Hypochloride of lime ... 3 lbs. 

After the perfect saturation, they are passed in a 

combined solution of tanning material and hypochloride 

of lime. This bath is thus formed : — 



Water 


100 gals 


Hypochloride of lime 


3 lbs. 


Catechu 


30 " 


Alum 


6 " 


Salt 


3 " 



The originality of this process consists in the use of 
bleaching powder (hypochloride of lime), in combination 



476 TANNING. 

with the other substances, or with any material used in 
the process of tanning; but we believe that the use of 
the bleaching powder is more injurious to the hide than 
beneficial, and we will not advise tanners to employ 
such a powerful agent. 

Bunting's Process. — The following are the proportions 
used in this composition: — 



Boiling soft water 


T gals. 


Dry elder leaves and bark . 


4 oz. 


Terra japonica . . ... 


. 15 lbs. 


Powdered nutgalls 


6 oz. 



Stir thoroughly until completely macerated, add then 
8 gals, of water, 1 lb. of potatoe starch, and 1 lb. of salt; 
the whole is stirred when it is ready to receive the skins, 
after having added 4 ounces of alum, and 14 ounces of 
whiting. In this process is not explained the utility of 
starch and whiting, and the materials used are too costly 
to permit their employment in the practice. 

Thompsons Process. — The composition used by this 
tanner is the following : — 

Polygonum bistorta . . . . 10 lbs. 

Geranium maculatum . . . 2 " 

Sulphate of copper .... i " 

Catechu in weak solution ... 1 bbl. 

Instead of catechu, tan bark or hot water can be used. 

L. Robinsons Process. — This process consists in the 
employment in combination with catechu, which has 
been purified by sulphuric acid, of carbonate, sulphate, 
or calcined magnesia, and sulphate of potash, for the 
purpose of tanning hides of every description. 

T. O. Eggleston's Process. — This process is similar to 
the above, and we do not think them worthy of con- 
sideration, as being impossible in large tanneries. The 
author uses terra japonica purified by sulphuric acid, in 



QUICK TANNING. 477 

conjunction with carbonate and sulphate of magnesia, 
and sulphate of potash. He prepares the tanning liquid 
called No. 1, with — 

Water 112 gals. 

Terra japonica .... 15 lbs. 

He stirs until dissolved, and adds: — 

Sulphuric acid ..... 3 lbs. 
Stir well, leave to cool and decant. 

For upper leather, to the above quantity of the liquor 
he adds i of an ounce of carbonate of magnesia, and -J-q 
of an ounce of sulphate of potash, and as much water to 
reduce the liquor No. 1 to one-half its strength. 

This liquor is good for ten good sized hides. The 
hides are put in and well stirred during the first two 
days. He keeps always the liquor No. 1 prepared, so as 
to increase the strength of the vat. Thirty-five gallons 
are added every second day, with 1 ounce of sulphate of 
magnesia. The hides are raised up to put in the fresh 
liquors. The operation is continued until the skins are 
tanned. 

This method is good for every skin the hair of which 
has been removed. According to its author, this process 
is a little quicker than the ordinary one, and the leather 
is better. 

A. Dietz's Process. — The features of this invention 
consist in swelling the tissues and fibres of the skin pre- 
vious to and during the process of tanning, by the use 
of saline liquors, so as to fit the skin to receive most 
easily and effectually the tanning material, and in using 
in connection with such saline liquors, tanning liquors 
of different and increasing strength, whereby the centre 
and inner parts of the skins are tanned as quickly, or 
nearly so, as the outer surfaces. 



478 TANNING. 

The author makes a weak liquor, at 2° or 3° by the 
barkometer, from any tanning material; in such liquor 
he mixes salt or alum, two ounces to the gallon, stirs well 
the whole; immerses the skins in this liquor and handles 
them till they are well saturated and the fibre fully 
swollen. The saline substance may be dissolved in 
water alone without any tannic material, and the skins 
saturated with this liquor, and after being completely 
saturated they are passed in the tanning bath. 

The strength of the bath in tannin has to be increased 
from 2 to 4 every day, and the skins are stirred and han- 
dled until they are tanned. 

The time required to tan is the following : — 

Sheep-skin . . . . 2 or 3 days. 

Calf " .... 8 days. 

Heavy leather . . . . 30 to 40 days. 

Sole leather . . . . 40 to 50 days. 

P. Daniel's Process. — The author prepares a bath of 
terra japonica at 10°. 

The first day for 30 skins he makes a bath with 8 
ounces of tartaric acid; he immerses the hides in and 
handles them four or five times. The second day he takes 
half a pail of the tannin solution, he dissolves i a pound 
of sal soda and adds to it a quarter of a pound of tartaric 
acid ; stirs well and puts in the vat containing the tannin 
solution, and repeats the operation as often as requisite. 

In the last week he adds i of a pound of bi-chromate 
of potash, and the leather is finished in the usual manner. 

Whatever are the merits of this process, the use of 
tartaric acid, on account of its high price, renders this 
method impossible in practice; and in addition we can 
never recommend the use of bichromate of potash on 
account of its oxidizing action on organic substances. 



QUICK TANNING. 479 

D. Needharns Process. — The following bath is pre- 
pared : — 



Hempseed 
Hops 
Sal soda 
Animal brain 



1 peck. 
1 lb. 
1. «< 

4 
4 



The whole is boiled in 8 gallons of water. When 
ready it is diluted with 40 gallons of water. 

The hides are soaked in this solution from 6 to 36 
hours. Then they are put in a tanning solution con- 
sisting of — 

Catechu 12 lbs. 

Divi-divi 4 " 

Alum . . . . . . 4 " 

Salt 2 " 

The originality of this process consists in the applica- 
tion to the hides of the above solutions, preparatory to 
treating them with the tanning liquor. 

R. Harper's Process. — The author takes — 

Wormseed 50 lbs. 

Thoroughwort . . . . 50 " 

Boneset 50 " 

Goldenwort 50 " 

He makes a liquor by steaming them, and uses this 
liquor in connection with — 

Terra japonica .... 15 lbs. 

Alum 10 " 

Saltpetre . . . . . 1 " 

These quantities are for 100 skins. According to 
its author, the use of the above-mentioned weeds, in 
combination with the aforesaid drugs, facilitates the 
process of tanning, and is cheaper than the usual process 
with bark. 

Our opinion is different. This process is more costly, 



480 



TANNING. 



and the leather must be of inferior quality to that made 
from bark, and this is easily accounted for, the above 
weeds containing very little tannin and much extractive 
matter. 

A. EilVs Process. — He takes — 

Soda 

Gum tragacanth 

Terra japonica 

Alum 

Common salt 

Saltpetre 

Prussiate of potash 

He dissolves in water, and leaves the hides in for ten 
days. We hardly believe such a mixture will work, and 
we do not see the necessity of using alum in connection 
with the prussiate of potash, which will render the pro- 
cess unhealthy on account of the prussic acid disengaged; 
and, besides this inconvenience, the materials used are 
too costly. 

J. Nuessley's Process. — He takes — 

Pyroligneous acid, from wood-tar, properly 







1 


lb. 






1 


<( 






. 12 lbs 






4 


<< 






3 


(< 






. . i 


lb. 






1 

4 


(( 



obtained by distillation 
Water 

Hydrochloric acid 
Catechu 
Alum 



1 gal. 

3 gals. 

4 ozs. 
II lb. 



He mixes the acid with the water and adds the hydro- 
chloric acid to the solution. Stir well. 
For 100 gallons of the above, he adds — 



Catechu 
Alum 



40 lbs. 
10 " 



And when cold put the hide in this bath. In three or 
four days the skin is tanned; heavy skins require three 
or four weeks. 

M. A. Bell's Process. — The hair is removed and the 



QUICK TANNING. 481 

skins are prepared in the usual manner. They are im- 
mersed in tlie tanning liquor from two to four days. 
The tanning liquor is prepared as follows : — 

Wood ashes .... 1 bushel. 

Water . . . . .50 gals. 

Let to settle and draw . . . 40 " 

He adds 40 lbs. of terra japonica, and boils until dis- 
solved. He allows to eool, decants, and it is ready for 
use. 

The author claims in this process that, by the combi- 
nation of lye with tannin, he is enabled to prevent the 
tanning liquors becoming sour or decomposed, and he is 
enabled to strengthen them without accumulating more 
than is necessary, and will tan skins in a shorter time 
and with less labor than by any other known process. 

JBIet's Process. — He operates in vats of oak or pine 
wood, which are kept in a room, the temperature of 
which is always between 77° and 86°. The hides are 
put into a vat containing river water; for 1000 lbs, of 
leather the vat contains 63 gals, of water and 5 lbs. of 
urea. Raise the hides four times a day; after three 
days the hides are well peeled, then they are well 
worked with a stone bottle, and immediately after they 
are peeled they are thrown into water and put anew in 
the vat with 5 lbs. of urea; let run on them tan juice 
strong enough; raise four times a day, adding every day 
some new tan juice stronger and stronger. Fifteen days 
after put them into a vat with water, and the juice 
which has been used to raise them. Six weeks after 
the Mdes are tanned. 

Baron's Process. — The river work and depilation by 

lime are the same as in the ordinary process, only that 

the author passes the hides during three hours in river 

water containing j^Vo^ of spirit of salt (hydrochloric 

31 



482 TANNING. 

acid), to destroy the small quantity of lime the skins may 
contain, and afterwards he washes in river water. This 
treatment with the acid terminates the perfect swelling 
of the hides, and they are ready to be tanned. 

Before tanning the color of the leather must be fixed 
so as to be of the usual shade. For that purpose he pre- 
pares a juice of oak bark, at 1° of the barkometer; in this 
juice he dissolves ^^-^ of madder, and passes the hides in 
this bath for six hours, so as to have the color take 
evenly. He leaves to rest one hour, and turns them 
over every hour. 

Twenty-four hours after the hides are ready to be 
tanned in the following manner : In river water dissolve 
catechu according to the number of hides to tan. The 
liquor is placed in a receiver-, covered with a filter, and 
provided with a rubber pipe to transfer the juice to the 
vats. 

The first vat contains juice at 1°, with a weak solution 
of alum; the hides are put in this mixture and are occa- 
sionally stirred during the first hours, afterwards they 
are raised every three hours. Next day they are placed 
in a vat containing juice at 2°. Raise four times a day, 
and let them drain two hours ; increase the strength from 
day to day until the hides are well tanned. Complete 
in the usual manner. 

Quick Process. — In this process the vessel has to be air- 
tight, and, at the same time, no metal can be used but 
copper. When the hides are taken from the wash all 
the water is expelled by pressure, they are then packed 
in a barrel, fixed so as to have a rotary motion, andSvitJ^ 
them the necessary amount of tanning material is mixed, 
and enough water is added, to keep moist the contents of 
the barrels. The main hole of the barrel is now closed, 
and the air pumped out as completely as possible; this 



QUICK TANNING. 483 

being done the stop-cock is closed, and a piece of lead 
pipe is added to the conducting tube. This lead pipe com- 
municates with a tank containing a solution of tanning 
material of the proper strength. If the stop-cock is now 
opened the tanning fluid rushes rapidly into the barrel, 
and when a sufficient quantity has been admitted the 
stop-cock is closed, and the barrel is now rotated for one 
hour, or half an hour, according to the quantity of hides 
contained in it. After two or three Hours' rest the rota- 
tion is again continued, until the operation is completed. 
The advantages of this process are to open the pores of 
the skins, and the tannin is not converted so quickly 
into gallic acid. 

The rotary motion facilitates the absorption of the 
tannic acid from the bark, and helps its labsorption by 
the hides, which are then tanned in less time than with- 
out rotary motion, as shown in the following table : — 

Time required for tanning Time required for tanning 

in vacuo without motion. in vacuo with motion. 

Calf skins, from . 6 to 11 days. . 4 to T days. 

Horse hides . 35 to 40 " . 14 to 18 

Lighter hides . 30 to 35 " . 12 to 16 

Cow hides (middling) 40 to 45 " . 18 to 20 

" (heavy) 60 to 60 " . 22 to 30 

Ox hides (light) . 50 to 60 " . 20 to 30 

" (first quality) 10 to 90 " . 35 to 40 

In this process a large percentage of bark is saved. 
Ouiofs Process. — The hides are swelled and depilated 
as usual. A vat containing 50 hides has the following 
dimensions: 3 feet wide and 4? feet high. The propor- 
tions of material to use are, for 50 hides weighing 500 
lbs.:— 

Catechu 150 lbs. 

Water 50 gals. 

Stir well until dissolved, and add 50 gals, of fresh water, and a 
solution containing 3 lbs. of lime. Mix the whole. 



484 TANNING. 

Put the hides in this bath and leave them in for eight 
weeks. During the first two weeks raise them once a 
day; the last 6 weeks raise them only once a week. 
Prepare another bath, and for this purpose take 25 gals. 
of the above which has been used, 25 gals, of fresh water, 
and 6 lbs. of white vitriol ; mix, put the hides in and 
leave them 4 days, being careful to stir every day. Raise 
and put them in 125 gals, of fresh water, leave them in for 
three days and then they are perfect. Complete them 
in the usual manner. 



CHAPTER CI. 

EESIDUES AND PRODUCT OF TANNERIES. 

Tanners call waste or residue, 1. The cuts and other 
parts of skins which being of any use are employed to 
make glue. 2. The wadding, horns, hair, spent tan, and 
old lime. 

The glue, or the cuts, is sold according to the quality; 
those of calf are always considered the best for the fabri- 
cation, of glue. 

Mr. De La Laude has advanced that cuts from skins 
prepared with tan juice were not fit to prepare glue. It 
is a mistake, for in Paris where heavy leathers are pre- 
pared in this manner, the cuts are sold for this purpose. 

The hairs, when they are mixed, are sold in France 
from |2 40 to $3 00 the hundred weight. Those of calf 
without any mixture are sold for $3 60 the hundred. 

The horns are sold by the hundred, according to their 
size and length. The old lime can be used for fence 
walls and even for foundations, or for manure. 

The spent bark can be used by gardeners for hot-beds 



RESIDUES AND PRODUCTS OF TANNERIES. 485 

and hot-houses. In France it is sold for this purpose by 
the wagonful at the rate of $1 00 to $1 20. 

According to Mr. De La Laude, 50 leathers prepared 
with lime give yearly a product of 66 francs ($13 20), 
the same quantity of leather prepared with barley 211 
francs (|42 20), and at last 50 leathers prepared with 
infusion of tan produce 254 francs (|50 80). 

A hide weighing 100 lbs., after being separated from 
the horns, hair, blood, grease, etc., gave by tanning 55 
lbs. of leather, sold at about 30 cts. per lb. Thus a hide 
of 100 lbs. cost $7 00, and is sold for $16 50. 

The industry of tanning gives a great value to the 
woods for the use of the bark. The price of the bark 
extracted from one hectare (2 J acres) of wood is valued 
at $^0 00. 



PART III. 

CURRYING. 



SECTION YIII. 

GENERAL WORK OF THE CURRIER. 

The derivation of Currier is from the Latin Corrlgere, 
which means straighten, weaken, etc., or better, from 
Coriarus, workman who works leather, called Gorium by 
Latins. The ancients, as with us, understood by currying 
the art of working or continuing to work tanned skins 
or leathers to give them suppleness, polish, color, etc., ac- 
cording to the use for which they were destined. If the art 
of tanning has necessarily preceded the art of currying, 
it is. easy to ascertain that currying has created the arts 
of the harness-maker, shoemaker, carriage-maker, etc. 

Of old, the currier applied himself only to hides of 
small oxen, cows, calves, goats, and sheep. Horse and 
mule hides were the lot of the Hungarian tanners, who 
alumed them, and passed them to tallow to manufacture 
the so-called German leather. Now these hides are cur- 
ried, and the leathers they produce take the place of 
goat and sheep-skins for upper leathers and boot legs. 

We must observe that, of old, curriers gave the name 
of cow-hides to' small ox-hides, which will not produce 
strong leather, while now they distinguish the hides 
by the name of ox, cow, etc. It is a known fact that 
cow-hides are to be preferred for currying to those of 



488 • • CURRYING. 

young oxen. Curried leathers have different names, 
according to their preparation and their use. The prin- 
cipal are tallowed leather, oiled leatJier, loaxed leather, 
oiled cow, etc. The principal operations to which leathers 
are submitted are the following: Soahing or dipping, 
treading or heating, stretching, oiling, tallowing, dyeing, 
and polishing. But before working them, the tails, fore- 
heads, teats, and parts of the extremities are cut off, and 
these remnants are used for uppers, soles, heels, etc. 

According to some manufacturers, there are some 
places where they work heavy leathers with the pommel. 
This process, which can be used only when the leathers 
are d^mp, strengthens them and renders them finer. 
However, this work being very hard, we indicate it 
without advising its use. In some countries curriers pass 
strong leathers in tallow and render them water-proof. 
The only objection to this process is that it is too long 
and difficult. 



CHAPTER CII. 

DIPPING. 

The first operation of the currier is that of dipping or 
softening leather. For this purpose, after cutting off the 
tails, foreheads and teats, they are put in a tub in which 
they stay until they are sufficiently moist to be worked. 
Of old the curriers used to dip a broom in water and 
sprinkle the leather until it was completely moistened. 
When the skin is well moistened, it is placed on the 
ground in a clean place, or better on a hurdle, and it is 
beaten with the feet until the water has penetrated all 



DIPPING. 



489 



its parts and it has become supple. That hurdle is rep- 
resented below. 



riff. 111. 




There are two kinds : one, manufactured by basket- 
makers, is composed of two strong posts about one yard 
long. In each post make seven or eight holes equally 
spaced, in which you introduce strong sticks to keep 
them spaced about a yard. Between these sticks inter- 
lace some ashed sticks. The other kind is made by a 
carpenter. It is formed with 15 strong posts; seven 
of them are placed below at equal distances, and eight 
above, notched to a wood and screwed to each other. 
These posts form eight ranks of parallel lines in one 
way, crossed at right angles by eight other ranks of par- 
allel lines, leaving between each empty spaces of about 
3 inches square. The workman to beat the leather wears 
large shoes made for this purpose, with three 
thicknesses of soles. For a quarter of an Fig. 118. 
hour or longer, with the heels the workman ^^^^3 
tramples upon the leather in every direction. 
The left foot maintains the leather firm, while the right 
heel pushes it with great force. For this purpose is 
also used a mace with a handle Hi feet long, with a 
mallet 4:^-^ inches long, 5i inches square, upon the two 
faces of which, parallel to the lines of the handle, are four 
egg-shaped pegs of wood, one and a half inches in length, 
which are finely polished, so as not to tear the moistened 



490 



CUllRYING. 



leather when beaten with it. Experiment has demon- 
strated that all the skins destined, to be tal- 
Fig. 119. lowed, not only ought to be beaten by the 
feet, but also rounded, and these two opera- 
tions require more care where the skins are 
hard and difficult to work. Firm skins re- 
quire to be more humected than others; it is 
the same for all the dry parts of these same 
skins. It is a bad process to moisten with a 
broom; they are much better done when 
dipped in a tub. 
The leather, after having been properly softened by 
these means, is placed upon the horse and subjected to 
the action of the cleaners. The horse consists of a strong 



Fig. 120. 




firm flat board, supported upon a frame by two uprights 
and a cross-piece, so that it can be made to slope at a 
greater or less angle. If not sufficiently heavy to be 
immovable, it may be loaded with weights placed upon 
the frame. 

A more convenient beam is that patented by N. Sar- 
gent. The upright is filled with adjusting screws, by 
which it may be elevated or lowered to any desired 
height, as may suit the comfort and convenience of the 
workman. 



DIPPING. 491 

Fig. 121. 




Formerly, and in some places now, three instruments 
have been and are used for cleaning and paring the 
leather : the sharp edge cleaner, the blunt cleaner, and 
the head knife. The latter alone is now used in Paris 
for this first working. This knife, called in French cou- 
ieau a revers, on account of the form of its edge, which 
is very much turned over, is from 12 to 14 
inches long, and from 4i to 5 2 inches broad, ^^S- ^'^^' 



and has two handles, one in the direction ^=^ 
of the blade, and the other perpendicular 
to it, for the purpose of guiding the edge more correctly 
over the surface of the skin. 

The round knife (lunette) is a circular knife from ten 
to twelve inches in diameter, with a round 4 or 5 inch 
hole in the centre, for introducing the hands. It is con- 
cave, of the form of a spherical zone; the concave part 
being that which is applied to the skin, and having an 
edge a little turned over on the side opposite to the skin, 
so as to prevent it from entering too far into the leather. 
Besides these, the sharp-edged and blunt-edged cleaners 
are sometimes used. The latter is usually 

made of an old knife, and is provided with ^^^^'^ ^^^^J^ 

two handles ; the former may be made of 
an old sword. 



492 CURRYING. 

Curriers are recommended to dispense with these 
cleaners, to use the head and round knife fgr shaving 
and paring the skins upon the horse, and to confine 
themselves to the employment of the stretching-iron for 
smoothing and scraping the leather, for filling up its 
weak parts, removing the creases, and the filamentous 
particles which project from its surface. 



CHAPTER CIII. 

SHAVING. 

The second operation of the currier is to shave the 
skins with the head-knife, above described. When the 
leather has been smoothed, it is shaved to secure uni- 
formity of thickness and regularity of surface, and that 
is the reason why every cow-skin which is destined to 
be tallowed or oiled must be shaved. When weak and 
thin parts are found in the leather, this operation is dis- 
pensed with J they are filled up with the stretching-iron. 

The head-knife is the only one used for calf and sheep- 
skins. Parisian curriers shave with the round-knife and 
head-knife. They use the French horse for paring off the 
borders of the skins, and the English horse for the other 
operations. 

Fig. 124. 




POMMELLING. 493 

For the purpose of paring with the round-knife the 
French horse is used also. However, in nearly all the 
shops, the table has been substituted for the horse, and 
it is on the table that the leather is smoothed. 

The above represents the workman smoothing the 
leather. 



CHAPTER CIV. 

POMMELING. 

All kinds of leather should be submitted to the action 
of the pommel, so-called because it clothes the hand and 
performs its functions. This instrument has a rectangu- 
lar shape, and is of different sizes, but is generally about 
13 inches long and 5 broad, and is made of dogwood. 
The upper surface is flat, and provided with a wide 
leather strap nailed to the sides, which is intended for 
confining the hand of the workman. The lower surface 
is rounded and furrowed over with transverse straight 
ridges and grooves. These grooves are sharp-edged 
isosceles triangles in section, and vary in fineness accord- 
ing to the size of the pommel, the largest being from 
seven-hundredths to one-fifth of an inch deep, and two 
or three- tenths of an inch wide. 

Figs. 125. 126. 

3 



A large kind of pommel, called the marguerite, is now 
employed for nearly all the operations in which the or- 
dinary one was formerly used. It is from 15 to 19 




494 CURRYING. 

Fig. 127. inches long, 5 inches broad, and of a thick- 
f^fj) ness in the middle of from 3 J to 4J inches, 
and at the end of from one and nine-tenths 
to two and two-tenths inches. As it is 
much heavier and more difficult to manage than the 
pommel, a peg or handle is placed at one end for the 
workman to grasp, while his arm is placed under a large 
strap, and his elbow rests upon a cushion at the other 
end. The grooves are larger and farther apart than 
those of pommels, and differ in size with that of the 
marguerite, which may be made for particular purposes, 
larger or smaller than the one which has been described. 

These instruments are those which are the best 
adapted to the purpose of giving flexibility and a granular 
appearance to the leather. The skin is first folded with 
its grain side in contact, then stretched out upon a table, 
and rubbed strongly with the pommel, or marguerite, each 
quarter successively being made to slide under the in- 
strument, over the leather below it, first towards the 
centre, and then back to its original position. This mode 
of working leather makes it extremely flexible. To give 
the proper grain, the skin is then stretched out upon the 
flesh side, and pommelled from head to tail and cross- 
wise. 



CHAPTER CV. 

STRETCHING. 

This operation is performed with the stretching-iron, 
which is a flat piece of thin iron or copper, a fourth of 
an inch thick at the top, and thinning off at the bottom 
into a blunt edge, shaped like an arc of a very large 
circle. It is about 6 inches long and 4 inches high, and 



STRETCHING. 



495 



is provided with a handle ten inches in length and five 
An iron or steel instrument is generally em- 



in height. 



Fig. 129. 



Fig. 128. 



ployed, as being less likely to wear out than a copper 
one; but the latter is preferred by many, since the 
leather is sometimes blackened and spotted by the iron. 
One made of steel is less objectionable on this account. 
Stretchers of other forms and dimensions than the one 
described above are sometimes used, but they vary very 
little from each other in construction. Those formerly 
used were without handles, and had a copper rim to pro- 
tect the hands of the workman. 

Fig. 130. 




The skin being placed upon a table, the workman 
grasps the stretching iron in both hands (central figure), 
and holding it nearly perpendicular upon the leather, 
forcibly scrapes the thick places so as to render them of 
uniform thickness with the rest, to remove particles of 
flesfi or projecting filaments, and to fill up the thin and 
weak spots. The leatlier is rendered smoother, softer, 
more compact, and equal throughout by this operation, 
to which all kinds of skins should be subjected ; and 
when thus treated, there is no absolute need of the ap- 
plication to them of oil or tallow. 



496 CURRYING. 



CHAPTER CVI. 

WOEKING WITH THE KOUND-KNIFB. 

The round-knife, as shown in the figure below, has 
already been described. The leather is submit- 
^5^ ^^^ ^^ ^^® action after its edges have been sloped 
oJBf with the head-knife, an operation which is 
performed upon the horse by shaving off a layer 
of two inches in breadth all around the borders of the 
skin. They are then worked with the round-knife upon 
the dresser, a cylindrical wooden bar fastened at a height 
of five feet three inches from the ground, by its two 
ends, to two buttresses projecting from the wall. 

Along the upper surface of this bar a thick cord is 
stretched.. Separate the end from the dresser, fold the 
breadth of the skin over it, the grain being within, turn 
over the skin and stretch it around the beam, its end being 
firmly held between the bar and the cord, which is still 
more tightly pressed down by the leather which envelops 
it. The figure below represents a skin stretched upon 
the dresser. 

Fig. 132. 




After the skin is stretched, the lower part of it is 
seized and confined in place by a pair of pincers attached 
to the girdle of the workman, and grasping the round 



WORKING WITH THE ROUND KNIFE. 



497 



knife with both hands, he works the leather with it from 
above downwards, removing the fleshy, thick, or project- 
ing parts. This paring requires the utmost care, and is 
generally done from tail to head, and sometimes across 
the grain. 

Fig. 133. 




The round-knife is occasionally sharpened upon an 
oiled stone, and the edge is kept turned over by a steel, 
so as to prevent it from entering too far into the leather. 

Fig. 134. 




This operation is performed only or chiefly in France 
for goat-skins, all the other kinds being pared with the 
head-knife. An ordinary skin can be pared upon the 
dresser in one hour, and six or eight dozen goat-skins in 
a day. Before being curried, hides are frequently cut in 
half, and are still oftener made into an almost square 
form by cutting ofi" the head and belly parts, leaving the 
tail still attached to them. These square hides contain 
all the best and strongest parts of the leather; the head 
and belly portions being the weakest, and only used by 
shoemakers for the finest or upper soles. 
32 



498 CURRYING. 



CHAPTER CVII, 

PREPAEATION OF STRETCHED LEATHER. 

The skins of cows and of young oxen made into crop- 
leather are the only ones fit for stretchers, and when thus 
prepared do not require the application of oil or tallow. 

All curriers do not follow the same method; some 
preparing the crop-leather, or that which has been tan- 
ned in bags, by the Danish plan. They dry the leather, 
moisten it, flesh on the horse, moisten a second time, 
scrape with the stretcher, and when thoroughly dry, 
slick it with the glass polisher so as to smooth the grain. 
Formerly to stretch a cow-skin the head was removed, 
as being too thick to be properly smoothed ; but it is now 
usually left on, as it forms a considerable addition to the 
weight of the leather. The skins are first cut in half 
from head to tail, the whole skin being too large to be 
properly worked, and are then deposited in tubs full of 
water, in which they are allowed to remain for twelve 
hours. 

When thoroughly wet, they are taken out and spread 
on the table and worked from head to tail with the 
stretching iron, or, if preferred, they are lightly pared 
on the horse. These operations being completed, the 
skins are well pommelled and worked with the marguer- 
ite, from head to tail and crosswise, and then dried. 

When stretched and deprived of the greatest part of 
their moisture, they are slightly dampened with a wet 
cloth upon the hair side, and scraped again with the 
stretching iron. The hair side is well moistened with a 
wet cloth, then the skins are dried, placed under the 



PREPARATION OF SLEEKED LEATHER. 499 

press, and after an exposure of three or four hours, they 
are hung up to dry. When nearly dry, pile them up in 
a dry and clean place, cover them with loaded planks, 
and the operation is completed. 

Leather prepared in this way does not require oil or 
tallow, and is not blackened. It is used by saddlers, 
harness-makers, and shoemakers for the soles of pumps, 
and the upper soles of heavy shoes. 



CHAPTER CVIII. 

PREPARATION OF SLEEKED LEATHER. 

This kind is principally intended for saddlers' and 
harness makers' use, and is made of strong hides. Ox- 
hides and thick cow-skins are generally preferred. 

After they have come from the tanyard, the hides are 
cut in two and are deprived of the head parts, soaked in 
a tub, and trod out, being careful not to allow them to 
become too thoroughly saturated with water. Then they 
lightly flesh them with the head knife, pommel and half 
dry them by exposure to the air. In this state they 
tread them out, hang them up to dry and tread out a 
third time; pommel on both sides, and at last hang 
them up until thoroughly dried. Each skin then has its 
weight marked with Roman characters. 

Before tallowing, the flesh sides are rapidly flamed, 
by being drawn over a blaze of fire from lighted straw, 
the object of which is to make them more penetrable to 
grease. The fatty matter to be used is left to the choice 
of the operator, but mutton suet is the best, and gives a 
finer lustre to the leather than any other, but is more 
expensive. In Paris the curriers use suet obtained from 



500 CURRYING. 

kitchen drippings. A hide of an ordinary size requires 
6 J lbs. of suet. 

Melt and heat the grease to the proper point, stretch the 

skin upon the table, and spread the tallow over the surface 

with a tallowing cloth or mop made of the fleecy parts 

of blanket stuff. This kind of mop is 15 to 19 

'^* ■ inches long; the handle is made by binding or 

^■j tying up from 11 to 13 inches of its length, 
leaving a tuft long enough to answer the purpose. 

Apply at first the grease on the flesh side, and then 
upon the grain, and more of it is rubbed over the groins, 
edges, and thin parts than over the rest, so as to increase 
their strength and body. A hide can be tallowed in five 
minutes. After being greased, fold the skins square, the 
hair side in, and soak in a tub during eight or ten hours j 
then tread them out in water, and beat with the mace 
until deprived of the watery contents. Moisten them 
again with a wet broom, or soak for a time; beat once 

Fig. 136. 



more in every direction. Pommel then with the mar- 
guerite upon the flesh side ; the hair side is pommelled 
from head to tail and crosswise, until the grain is well 
smoothed, then the skin is placed upon the table with 
the hair side up, and the surface is smoothed by the use 
of the stretching-iron. 

Blacken the leather now while still upon the table ; 
if the leather has become too dry, moisten it before the 



PREPARATION OF SLEEKED LEATHER. 501 

blackening, because a certain degree of humidity is ne- 
cessary to enable it to receive the color. For this pur- 
pose dip a brush of horse hair in the composition and 
rub thoroughly with it in every direction. After the 

Fiff. 137. 




first blacking, dry the leather to three quarters, by ex- 
posing it to the air ; pass again the stretching iron over 
the surface, being careful not to scratch it. You secure 
uniformity and smoothness of surface by moving the 
instrument constantly in one direction. To make the 
leather appear thicker and uniform, pare off the edges 
with a hooked knife. 

For sleeked leather two applica- ^' ^ 

tions of black are required, and if 
any part of the surface remains of 

a red color, a third may be requisite. The second coat 
is applied in the same manner as the first ; the leather 
is then partially dried, and the surface sleeked, until all 
the marks of the stretching-iron have disappeared. When 
the leather is of a fine black color and perfectly dry, 
expose it to the press for two weeks, which increases 
its density and firmness, the excess of tallow being 
pressed out. If moist when placed in the press, it is 
usually found covered with mould when taken out. 

In order to give the last dressing, wipe the hair side 
well so as to remove any portions of remaining grease, or 



,502 CURRYING. 

the mould formed on the surface. Polish it with sour 
beer or barberry juice, and sleek the surface with a very 
smooth stretching-iron. 

If any spots of grease or defects remain on the sur- 
f^ice, rub gently those parts with a cloth dipped in the 
polishing liquid, until perfectly bright. At last hang up 
the leather to dry in a shady place. 

Parisian curriers use for blacking hatter's black, com- 
posed of logwood, nutgalls, gum, and sulphate of iron. 
The last dye is made as follows : Cover with sour beer, in 
a deep wooden vessel, scraps of old iron, and leave them 
in contact for three months. It forms a red liquor of 
acetate of iron, which blackens the leather better and 
quicker than the solution of sulphate of iron. 

Another liquor, less expensive and more quickly made, 
is thus prepared : Mix sour beer with barley yeast, leave 
twenty-four hours, and then add it to a solution made by 
boiling sulphate of iron in vinegar, being careful to re- 
move all the yeast from the surface. 



CHAPTER CIX. 

COMPARISON OF SLEEK LEATHER WITH ALUM-DRESSED 

LEATHER. 

Lately the Imperial Board of Military Horse Inspec- 
tors at Vienna put the questions to the Austrian Cham- 
bers of Commerce, whether, taking into consideration the 
quality and nature of sleek leather, and the greater cost 
of articles of horse gear made of this material, more 
durability was possessed by it than by alum-dressed 
leather proportionally, and inquiring as to what per cent, 
sleek leather excelled alum leather on this head. The 
questions propounded were answered as follows :-^ 



COMPARISON OP SLEEK LEATHER. 503 

"Althougli the various articles manufactured out of 
sleek leather, as a rule, come higher in price by at least 
20 per cent, than similar articles made of alum-dressed 
leather, still the price of the former, in view of their 
respective qualities, can only be said to be apparently 
higher, for which reason the use of articles made of sleek 
leather is to be recommended. Alum-dressed leather is 
far from possessing the durability of sleek leather, and 
it is a well-known fact, that if alum-dressed leather is 
exposed to humidity it grows soft and therefore ductile, 
by which when the horses draw the traces are stretched 
out, and the power employed to set the load in motion 
is weakened. 

"On this account, especially for the harness of teams 
used in transportation and in the artillery service, where 
a greater amount of strength is necessary, sleek leather 
must always be preferred to alum-dressed leather. 

" And even if, independent of what we have already 
said, the articles of horse gear from alum-dressed leather 
do come cheaper, still this economy is only seeming and 
not real, for the articles made from sleek leather will 
generally stand almost double the wear of those made 
from alum-dressed leather, and therefore they are in fact 
worth more, by at least 20 or 30 per cent. 

" It is unnecessary to remark on what account sleek 
leather possesses a greater durability than alum-dressed 
leather. The one is a bark-tanned leather, the other a 
so-called mineral-tanned leather, whose pores are simply 
filled out with the material in an insoluble form, and 
when worked upon by water and solvents they easily 
become cleaned out again. In fact, alum-dressed leather 
when exposed merely to a damp air, untans itself; that 
is to say, it returns to its original raw condition. When 
bark-tanned leather happens to untan, the untanning is 



504 CURRYING. 

a very slow process indeed, because the combination 
formed between the tanning material and the fibres of 
the hide is much closer and firmer than in the other case, 
where merely the pores of the hide are impregnated with 
the tanning stuff. With regard to the estimate of the 
difference in cost and the durability of both kinds of 
leather, we believe a practical calculation will show that 
no other estimate could be given truthfully." 



CHAPTER ex. 

TALLOWED OR GRAINED LEATHER. 

Grained or tallowed cow-skins are those, the grain of 
which has been brought out, instead of being smoothed 
down and polished, as the sleeked leather. They are 
softer and more flexible than the latter, and more water- 
proof, and are consequently much used by trunk-makers, 
saddlers, and harness-makers. The largest ones are em- 
ployed for carriage tops. The finest cow-skins, not cut 
in half, but entirely dressed, are selected for the prepara- 
tion of this kind of leather. Tread out the skins with 
the feet until all irregularities of surface have disappeared, 
then pare them with the head-knife to secure^ perfect 
uniformity. The edge of the knife should be straight 
and even, so as not to streak or scratch the leather ; then 
dry the skin partially and work it again with the foot while 
in this state, and tread it out so as to free it from all 
depressions of surface. 

Dry the leather partially, beat it once more, roll it up 
first upon the flesh, and afterwards upon the hair side, 
the creases then disappear; if too hard, moisten it by 



TALLOWED OR GRAINED LEATHER. 505 

sprinkling water over it. Pommel it with the cork from 
tail to head. 

Dry the leather sufficiently to allow an insensible 
amount of moisture to remain in it, fiame on both sides 
and tallow as already described. Some tanners are in the 
habit, before this process, of sprinkling water with a 
brush over both surfaces, so as to increase the pliability 
of the leather. This practice is improper, as the excess 
of water prevents the grease from thoroughly penetrating 
the substance. A cow-skin requires from three to four 
pounds of tallow, and a thick calf-skin about one pound. 

After being tallowed, the skins are rolled and left 
folded with the hair side within for some days. They 
are folded square, and placed to soak in a tubful of water 
for eight or ten hours, and worked in the water until the 
excess of grease is worked off. The soaking has been 
sufficient when the surface assumes a uniformly white 
appearance. 

To bring out the grain, the leather is well worked 
with the marguerite, and the hair side is pommelled, 
then both sides are cleaned w;ith a horse-hair brush, and 
the creases are taken out from the parts which have been 
folded, by the use of a smooth stretching-iron, the opera- 
tion being conducted on a clean table. Then 
the skins are sprinkled with water, cleaned ^^^' 
again, doubled up and hung out to dry, re- \ — / 
touched with the stretching-iron, and at last 
slightly moistened before the application of the black. 

The blacking composition is prepared and applied as 
for sleeked leather. Then dry partially the skins, black 
them a second time, smooth them with the stretching- 
iron, wipe, fold up with the hair within, and pile them 
upon each other. Then take them down, blacken a 
third time, smooth and wipe as before, and then dry 



506 CURRYING. 

them perfectly. Then give them a coat of sour beer, and 
work the four quarters with the marguerite, pommel the 
hair side across, and rub with a piece of old blanket and 
apply a second coating of sour beer. When thus smoothed 
and cleaned, bring out the lustre by the use of the 
stretching-iron by mopping with the old flannel, and by 
rubbing the surface lightly with a smooth, compact piece 
of woollen stuff dipped in the barberry juice. Then pom- 
mel the surface at fir^t obliquely, afterwards across the 
breadth of the skin, and at last from tail to head, so as 
to round off the grain as much as possible. 

To give the last dressing to the leather, .treat it again 
with sour beer, expose anew in the air until dry, and rub 
once more with a cloth dipped in barberry bush juice. 

It takes a man from eleven to twelve days to prepare 
completely a dozen black skins. 

Tallowed hides are used by trunk-makers, harness- 
makers, and saddlers, and serve for saddle flaps and car- 
riage covers, the largest being used for carriage tops. 

Different materials are used to give a lustre to skins of 
this kind, as sumach, hot ooze and water, sour wine, or 
weak brandy. Gum Arabic and sugar dissolved in sour 
beer furnish an admirable liquid. Many other means 
are employed for the purpose of giving a gloss to the 
surface, some consisting of sugar and molasses dissolved 
in beer, others of infusion of cassia in beer and vinegar, 
etc. All these substances are less expensive than barberry, 
and quite as efficacious. 

Grain Black. How to Improve it. 

If this subject was given to a chemist for solution, he 
would analyze the blacking, and hope by changing its 
component parts to cause the desired effect. The most 
that can be said for the best patent liquid grain which is 



TALLOWED OR GRAINED LEATHER. 507 

now sold is, that it is a great improvement both as to 
quality and economy over the liome-made hlach, made 
from pyrolignite of iron. 

We do not ignore»the fact that many curriers of grain 
leather profess to make a perfect black which will stand 
.on hemlock; but we have never seen such black, and 
think we should have seen it if produced in this country. 

Black, as applied to the coloring of leather, is a rela- 
tive term. We have recently seen some tanned grain 
leather, i. e., leather tanned in salt and alum, which came 
from Japan, which was so much blacker than any black 
we can make* that ours looks brown in contrast. 

Now if the curriers of Japan can thus grain black 
tanned leather, we certainly should not despair of grain 
blacking all bark tannages. 

While the chemist seeks a remedy in a new analysis 
of the blacking, a practical tanner must seek a remedy 
in the preparation of the leather. 

Our curriers have little or no difficulty in grain black- 
ing leather tanned in oak bark or sumach. Why is this? 
The practical answer is, that they hold more acid than 
hemlock, but whatever the cause, we know that the pre- 
sence of either of these will unite with or take blacking 
and retain the color for a long period. 

In furtherance of this view of the case, we think it 
will have been observed by curriers that hemlock leather 
that has been tanned in old sour liquors, will take grain 
black much more readily than leather tanned in fresh 
bark and liquor. Some leathers have an old sour smell. 
These leathers of hemlock when otherwise well prepared, 
will be found to retain the black much longer than the 
fresh leather tanned out mostly by handling and by fre- 
quent change of liquor. If this is true, then it goes to 



508 CURRYING. 

show that the acid in the hemlock is the same in kind, 
but not in quantity, as in the oak and sumach. 

We must then remove as far as possible the hemlock 
tanning from the grain, and substitute sumach or oak. 
How can this be done? 

The hemlock skins or sides should be milled either in • 
a wheel or stock, until the liquor with which the leather \ 
was tanned is removed from the surface as far as possi- 
ble, then the grain should be well scoured on a table; 
after which the leather should be handled for a few 
days in a warm oak or sumach liquor. If this process is 
thoroughly carried out, hemlock leather may be made to 
take a tolerably fair leather. 

This is the process in use by most curriers in Newark 
and New York, who have the proper facilities, but unfor- 
tunately too few have such facilities, and hence the 
miserable attempt to black grain hemlock. We have 
not noticed the various methods employed to hill the 
grease, nor have we said anything about the various 
secrets for manufacturing the blacking, as we assume the 
cause to be want of acid, so we would supply this, and 
that of a quality and kind which is known not to injure 
the wearing qualities of the leather. This done, and 
hemlock leather may be blacked on the grain success- 
fully. 

But the harness leather manufacturer says, this milling 
and scouring process removes the weight. This is true. 
But the old grain must be scoured out, and the milling 
or wheeling process will greatly facilitate this. Besides 
the old grain to be removed, there is a large amount of 
tan liquor and bloom which must be removed ; if not, the 
leather will spew the oil, and otherwise make a slovenly 
finish. 

If we can successfully compete with the French in 



TALLOWED OR GRAINED LEATHER. 509 

grain blacking calf, colt, and horse leather, then there is 
no reason why the prevailing and very desirable fashion 
of shoes for ladies ahd children should not be maintained. 
But if hemlock leather is used as at present, so imper- 
fectly blacked that a few days' wear will change the 
color to a foxy hrown, then we may expect to see the 
fashion change as soon as the price of cloth or morocco 
shall again come within reasonable bounds. 

Why is it that goat morocco does not thus change 
color? Simply because hemlock tanners have not ven- 
tured to lay their hands upoil the manufacture. What 
would be thought of the sanity of a hemlock tanner who 
should insist upon tanning goat-skins in hemlock, because 
forsooth he might save a few cents on each skin, as be- 
tween the cost of hemlock bark and sumach? While 
the hemlock tanners would not think to venture on grain 
goat, they do venture and insist upon tanning grain calf, 
and the result is what we all see. 

Now the difference between the cost of oak bark and 
hemlock in the tanning of calf is so trifling as hardly to 
be worth mentioning, and yet a very large majority, 
perhaps eight-tenths, of all the calf-skins taken off in this 
country are tanned in hemlock bark. 

The effect of our system of calf-skin tanning has been 
to throw the business into French hands of supplying 
our people with the finer descriptions of skins, both grain 
and wax. But this should not be, and must not longer 
continue. 



510 CURRYING. 



CHAPTER CXI. 

WATEE LEATHER. 

The name of water leather is applied to the larger and 
finer neat-skins sent directly from the tanner to the 
currier, who does nothing but pare and expose them to 
the air before sending them, still in the wet state, to the 
carriage-maker. The latter does not receive those skins 
until about to make use of them. He places them upon 
the carriage, fixes them in position, and without making 
other changes, blackens and varnishes them. 



CHAPTER CXII. 

OIL LEATHER, 

Two liinds of oil leather are manufactured, one black, 
intended for harness-makers, the other uncolored, for 
shoemakers' uses. This leather is exceedingly durable, 
and the most entire and well-tanned skins are always 
selected for its preparation. Whether skins are intended 
to be blackened or not, in either case they are dipped, 
but after this operation has been gone through, they are 
kept separate, as the process is different for both kinds. 

The kind intended to be blackened on the hair side 
should alone be beaten. The operation is then finished 
with the round-knife. At first they are treated like tal- 
lowed hides, that is, dipped and then beaten, if the 
intention be to trim them with the round-knife, and 



OIL LEATHER. 511 

they are fleshed if this is not the case. They are then 

worked with water in a cask with a long pestle. A 

Fig. 140. Fig. 141. 



o 




number can be operated at a time, and as the object is 
to make them pliable and soft, they are often treated in 
this way seven or eight times, being each time redipped 
and worked in the same manner. 

After the skins have been thus worked, the flesh side 
is stretched upon marble tables, and the hair side worked 
with the stone, and to extend them thoroughly the 
stretching-iron is well laid on, by which process all the 
water is pressed out. The stone used for the purpose is 
a piece of good grit stone, set in a handle in the same 
manner as the stretching-iron. The skins having in this 
way been freed from the greater portion of their watery 
contents, are then exposed for the purpose of drying 
either in the open air or within the building, one hour's 
exposure usually being sufficient in summer, while in 
winter many more are required. After being sufficiently 
dried, they may at once be held in readiness for the ap- 
plication of the oil. 

Fish oil is sometimes used for this purpose, but it has 
been proved by experience that train scouring oil is the 
best for this purpose. Train scouring oil is a mixture of 



512 CURRYING. 

fish oil and potash which has already served to clean 
skins converted into chamois leather, and many advan- 
tages are obtained by using it. It has more density than 
fish oil, and is more completely absorbed by the leather. 
Its saponaceous quality contributes to give softness and 
tenacity, and less of it is required than of oil. Its qual- 
ities should be well ascertained before using it, for if it 
has not been well boiled, and if it contains water, it will 
not possess the proper penetrating power. 

According to De La Lande, neat's foot oil adds to the 
qualities of the leather. To obtain it it is only necessary 
to boil the foot thoroughly in water, draw off the liquor 
and place it in a kettle with water to the boiling point. 
Boil this for twenty-four hours ; the pure oil rises up to 
the top; draw it and place it in another kettle at about 
125°. Let it remain at this temperature for twenty-four 
hours ; cool off. Three different layers of oil rise to the 
surface ; draw them off separately. The heaviest of these, 
according to De La Lande, is found to render leather 
perfectly water-proof. 

It is in^possible to employ the scouring alone, whatever 
is its quality; it must invariably be mixed with fish oil. 
The proportions of the mixture cannot be accurately 
given, as they depend upon circumstances, the tempera- 
ture of the air, quality of the leather, dressing intended 
to be given to it, peculiar mode of operation, etc. etc. 
In summer a small quantity of oil is added to make the 
mixture, while in winter a larger quantity is required. 
Poor and thin hides, which have been left too long a 
time in the lime pits, require but little oil and a good 
deal of scouring, because they cannot retain much of the 
oleaginous matter, and will absorb too quickly that which 
has the greatest penetrating power. When the skins are 
exposed to the action of the mixture, they imbibe upon 



OIL LEATHER. 613 

the i5rst application much more than upon the second. 
The denser the scouring oil the more oil is required, but 
the quantity of the latter which is often made to amount 
to one-quarter of the mixture, should never exceed one- 
half of it. 

Experience has shown that for a neat-skin weighing 
from 15 to 16 lbs., 4 lbs. of oil material are required, and 
that 10 lbs. are expended upon a dozen calf-skins weigh- 
ing 28 lbs., thus giving the proportion of about one-quarter 
of their weight of oil for the former, and one-third for 
the latter. 

Skins intended to be oiled should contain just enough 
water to enable them to yield a small quantity upon 
being wrung out. If they be dry or slightly moist, they 
will absorb the oil too rapidly, while it is essential that 
their substance be gradually penetrated by it. When they 
are too wet they take it up slowly in proportion as they 
lose their water. Therefore before oiling them the ope- 
rator should carefully ascertain that they are just wet 
enough for this purpose, and should moisten again those 
parts which have become too dry. The other extreme 
should be as carefully guarded against, because when the 
hides are too wet, too much of the scouring oil is con- 
sumed in forming a soapy compound with the water. 

After the skins have been oiled on both sides, and the 
workman has uniformly distributed the oil over the sur- 
faces with the hand or the tallowing cloth, he hangs them 
up by the hind quarters and allows them to remain in 
the air long enough to absorb their contents of oil, taking 
care not to let them be exposed to the extreme heat of 
the sun, or to a great draught of air, as, if they be dried 
too rapidly, the oil will not penetrate them gradually. 
Ten or twelve hours of exposure are sufficient in summer, 
while in winter it requires two or three days. The 
33 



514 CURRYING. 

bellies of neat hides require less oil than the other parts, 
while on the contrary those of calf-skin absorb more. 

There is no uniform method for oiling skins. In some 
establishments the oil alone is applied to the hair side, 
while a mixture of oil and scouring is placed on the flesh 
side; in others the mixture is applied to both surfaces. 
Again some curriers make use of no oil whatever, but 
apply the scouring oil to both sides, taking care only to 
stuff the flesh side most plentifully with it. These differ- 
ent modes appear to succeed equally well, and we refrain 
from condemning any of them, but we must observe that 
care should be taken not to give the hair side too great 
an amount of scouring, or it will be very difficult to give 
a gloss to the surface. Skins intended for saddlers 
require by one-third less of oil stuffing than is needed for 
shoemaker's leather. 

After the skins have become sufficiently dry, they are 
fulled and recharged with some fish oil and a lesser 
quantity of scouring oil, again fulled, and at last the hair 
side is. to be thoroughly scoured by a brush dipped in a 
lye of potash. Immediately after this the skins are 
blackened, care being taken to keep the borders clean. 
The blacking has already been described, and is applied 
in the same manner. After the first blacking, pommel 
the skins crosswise, apply a second coating of black, and 
expose them to the air until completely dry. Then beat, 
pommel, and trim them, pass over with the head of the 
round-knife, rub with the cork, and terminate the process 
by lightly rubbing the hair side. 

These last operations are diflerently performed by 
different curriers. Some, after the first coating of black, 
do not full the skins, but stretch them with the stretch- 
ing-iron upon the table. They moisten the hair side, 
pass over it the solution of potash, and give a second 



OIL LEATHER. 615 

coat of blacking. To smooth and to impart grain they 
pommel them from tail to head, and across the grain. 
This last method is preferable. 

As harness-makers need for their purposes very strong 
skins, square oiled hides are prepared especially for 
them, or skins the head and belly pieces of which have 
been cut off, by which each skin is reduced to 4 J feet in 
length, and about three feet in breadth. The following 
figure represents a square oiled hide or croupon. 




Oiled Leather. — We class under this head a kind of 
leather prepared without tannin or alumina, and having 
the grain surface of the skin removed. Fish oil is the 
principal substance employed, and has no chemical action 
on the tissue. The skins imbibe the oil by mechanical 
force, which expels the moisture and with it all putres- 
cent matters soluble in cold water. This leather is com- 
monly known by the name of Chamois, because it was 
originally made from the skin of the wild animal of that 
name. It is also called Lash leather. Its use is now 
almost exclusively limited to domestic purposes, being 
employed chiefly for washing and polishing farniture. 

The preliminary operations are the same as for tan- 
ning, and the process can be applied to goat, sheep, 
lamb, deer, etc., skins, care being taken to choose the 
finest and most perfect. 

The skins are brought to the state of Pelt by washing. 



516 



CUERYING. 



liming, fleecing, beaming, and branning, in the same 
manner as for kid leather; they are subjected to the 
frizzing operation, which is rubbing them with pumice 
stone, or working them under the round edge of a blunt 
knife. This operation removes the grain surface, equal- 
izes the thickness of the skin, renders it pliable, and 
exposes a softer surface. 

Wring out the skins and transfer them to the trough 
of a fulling mill, and subject them to the continuous 



Fig. 143. 




action of the wooden hammer until nearly dry, then re- 
move them, spread them upon the table, and sprinkle 
them over the surface with fish oil. Fold them in bun- 
dles of four, and return them to the trough and beat 
them as before from two to four hours, as may be neces- 
sary to produce a perfect impregnation with the oil, after 
which take them out again, open, expose them to the air 
for a short time, and then besmear them with grease and 
full as before. Repeat these manipulations eight or ten 



OIL LEATHER. 517 

times, until the skin becomes thoroughly impregnated 
with oil. One gross of skins requires from three to five 
gallons of oil. 

After the oil has been well beaten into the pores, and 
there is no appearance of greasiness, take the skins out 
and suspend them by hooks, to wooden hangers running 
across a drying chamber, about six feet high and twelve 
feet square, heated by steam pipes. This treatment 
causes a slight fermentation, which dilates the pores, and 
promotes the intimate incorporation of the oil with the 
animal fibre. 

Remove the excess of oil by immersing and handling 
the skins for one hour, in slightly heated potash lye at 
2° Beaum6, which converts it into a soluble soap. Wring 
them at the peg, dry, finish at first on the stretcher, 
and smooth at last with rollers. To give them a buff 
color, dip them merely in an infusion of oak bark, which 
in this case is used as a dye. 

The fulling mill consists of two stocks, the head cov- 
ered with copper, being attached to a long beam or handle 
lying in an inclined position. Near the lower end of 
each a wheel revolves, by which each hammer is raised 
and dropped through a space of about a foot into the 
trough beneath. The upper or handle end of each stock 
is adjusted so as to work on a pivot or axis, and the 
stocks being set in action the two descend and rise alter- 
nately, and beat the skins uniformly until perfectly dry. 



518 CURRYING. 



CHAPTER CXIII. 

WAXED LEATHER. 

Waxed skins are those which have been rubbed over 
with melted wax, and maintained at a heat sufficiently 
great to allow it to penetrate the leather. This mode 
being costly very few are now prepared, principally as 
saddlers and harness-makers no longer buy them. The 
name is now, however, applied almost entirely to tallow 
hides which have originally had great consistency, being 
very carefully prepared. Some curriers, to give great firm- 
ness to certain skins, add to the tallow from one-eighth to 
one-quarter of wax. Generally smooth, sleek skins, with 
this property of great firmness, are used and sold by car- 
riage-makers as waxed skins, and are held in great esteem 
for their beauty and durability. 



CHAPTER CXIV. 

ENGLISH HIDES. 

These skins are so called which are made pliable by 
means of tallow, and retain their reddish or yellowish 
color. They select for this purpose tanned skins of the 
best quality, white on the hair side, clean, and free from 
greenness. They are dipped in the same manner as 
sleeked leather, and are carefully handled, as the least 
spot renders them unfit for use. After having been 
dipped and exposed to the air, they are then worked and 



ENGLISH HIDES. 519 

pared, and are well pommelled on both sides to efface the 
wrinkles; they are thoroughly dried before being tallowed. 

When done, wet the hair side with a clean cloth dipped 
in pure water, so as to prevent tallow entering the weak 
parts. The tallow applied to the flesh side should not 
be as warm as that used for the tallow hides and sleeked 
leather, and as the principal object of the process is to 
make them retain their natural color, only a small quan- 
tity should be applied, so that it shall not fully penetrate 
to the hair side. The skins are soaked half an hour in 
clean water after they have been tallowed. The process 
is thus described : " After the skins have been soaked, 
they should be worked in water, and a light and uniform 
coating of fish oil, or what is better, linseed oil, is spread 
over the hair side with a piece of wool or cloth. Then 
they are dried, and the process is finished as for sleeked 
leather, except that a stretching tool of copper is used 
instead of iron, which might spoil the surface. Dry 
thoroughly the skin, and apply on the hair side a color 
made of French berries. One-half a drachm of berries 
dissolved in one quart of beer is sufficient to color six 
hides. The color is laid on carefully so as to secure an 
uniform coating, and as briskly as possible, otherwise the 
skin will be spotted or discolored. 

"After the skins are colored, dry them in the open 
air in the shade, because, if exposed to the heat of the 
sun it will cause the oily matter to penetrate through to 
the hair side and discolor its surface. The barberry is 
not required, but it is sufficient to rub the skin until it 
becomes dry with a small cloth or piece of linen, by 
which the surface is rendered sufficiently smooth and 
polished. Some do not even color skins of this kind, but 
content themselves with smoothing them. 

"Another different method is sometimes followed. 



520 CURRYING. 

When the skins meant to be yellowed have been pre- 
pared, pommel them to make the inequalities of the 
surface disappear, and full them in a cask containing 

Fig. 144. 




clean water. Place them then upon a marble table, with 
the flesh side uppermost; replace again upon the stone 
with the hair side up for staining, and drawn out with 
the stretching-iron. This should be pressed down very 
firmly, for the purpose of stretching the leather and of 
making it compact and firm. Then dry them a little, 
and again and again treat them with the stretcher of 
copper, care being taken to dry them well after each 
dressing with a clean woollen cloth. After this apply 
linseed oil to the hair side; and a composition of equal 
parts of fish oil, scouring oil, and fine white tallow, 
melted together and passed through a hair-cloth sieve, 
is used for the flesh side." 

In order that the shoulders and legs should have a 
uniform color with the body, it is proper to apply a less 
amount of liquid to them. After this oiling, the skins 
are dried by hanging them upon a rod with its ends 
passed through the tail and one of the legs. When dry 
they are placed anew upon a marble table, the flesh side 
is stretched out with a warm stretching-iron, for the pur- 
pose of cleaning them and making them compact. The 



WHITE LEATHER AND COMMON RUSSET. 521 

hair side is then placed upwards, moistened with a little 
clear water, treated with the copper stretcher, dried care- 
fully with a clean rag, and passed over with the stretcher 
once more before the final drying. Sometimes they use 
a color made with a little Brazil wood, Yellow berries, 
and glue heated together. This color is passed rapidly 
and lightly upon the hair side, and the leather is then 
stretched and exposed to the air until perfectly dry, and 
is finally sleeked with a piece of glass attached to a handle 
like that of a stretching-iron. Skins thus prepared are 
higher priced than tallowed leather, and are chiefly used 
by harness-makers. 



CHAPTER CXV. 

WHITE LEATHER AND COMMON RUSSET. 

White Leather is used principally by shoemakers for 
the uppers of large shoes, the hair side being placed 
within. The skins are not worked up whole, but are 
made into square hides by cutting up the heads and belly 
pieces, which, being too thin for the purpose for which the 
leather is employed, are used for the first or upper soles. 

Dip the skins well at first and scrape them carefully 
with the head-knife without being shaved. Then treat 
both sides with oil and train oil scourings, dry, beat out 
with the feet, trim on the borders, press and pommel 
them to efface the creases. Complete the preparation by 
pommelling with the cork, so as to smooth the flesh and 
grain the hair side. 

This leather is well stuffed, each skin absorbing usually 
3i lbs. of oil and train scouring oil. Some curriers pom- 



522 CURRYING. 

mel only these skins on both sides, and dry them. They 
assert that they are finer than when beaten. 

Common Russet is prepared as blackened leather, ex- 
cept it is allowed to absorb grease to saturation, so as to 
increase its strength and pliability. For this purpose, 
after the skins have been tallowed and partially dry, 
they are saturated with train oil scourings on both sides, 
about Ih lb. being used for each skin. This leather 
preserves nearly its original color, and is used principally 
for pump-valves, mail bags, etc. etc. 



CHAPTER CXTI. 

CUERYING OF OALF-SKINS.— OILED CALF-SKINS. 

Calf-skins are sometimes prepared in the same manner 
as neat's leather, the thickest and largest of them being 
used for the same purpose as square hides; but the latter 
being commonly employed in the manufacture of soles, 
the calf-skin leather being only used for uppers, and 
being consequently required to possess more pliability 
and softness, must be treated by processes differing from 
those to which thick leather is subjected. 

Oiled Calf-Skins. — As soon as the skins are taken from 
the pit, dry them immediately, scrape and tread them 
out under the feet, and then oil on both sides. In winter 
you can use warm oil. As for cow-skins use a mixture 
of equal parts of oil and scouring train oil. If the train 
oil is very clear, it can be used alone. A dozen of calf- 
skins weighing from 30 to 36 lbs. generally require from 
10 to 12 lbs., though experience alone can guide the work- 
man to judge the amount the skins will absorb without 
injury. Avoid the use of an excess of fatty matter, as it 



CURRYING OF CALF-SKINS. 523 

tends to make the leather too soft and flabby. If the 
skins have been exposed too long in the lime they do not 
take up as much oil as those which have not been thus 
injured. After the oiling, dry the skins and dress and 
soften them by beating them with the feet, and bring the 
grain in the usual manner. If the skin is intended to be 
waxed, or converted into grained or stamped leather, 
they do not require to be worked with the feet. 

In order to cleanse and soften the leather and prepare 
it to receive the black, dip a brush in a solution of pot- 
ash, made by dissolving about one pound of potash in a 
bucketful of water, and pass it over the hair side. If 
the solution is stronger it injures the leather, but the 
above is sufficient to saturate the excess of oil and enable 
the black to adhere more readily to the surface. When 
this operation is completed, apply at once the liquid 
blacking as above, being careful to not lay on a large 
enough quantity to penetrate below the surface of the 
leather. 

Pommel the skins then from head to tail with a me- 
dium sized pommel; use four parts of oil and one of 
scouring train oil to smooth down the long ridges which 
traverse the leather in different directions. 

Apply then a second coat of black, and, if necessary, 
charge again the leather with the oily mixture, and dry 
thoroughly in the air. Then tread it out, pommel on 
both sides, pare down on the borders with the head-knife 
and scrape with the round-knife. To complete the prepa- 
ration, pommel with the cork, and rub lightly over the 
grain with fish oil to deepen the color, which would have 
been injured by the previous operations. 

Sometimes curriers follow another method. After the 
skins are dried and oiled, they soak them in a tub until 
sufficiently damp, while they are not thoroughly pene- 



524 CURRYING. 

trated through. They are then pommelled lengthwise 
and blackened. Then they are pommelled crosswise, 
blackened a second time, charged with the oily mixture, 
thoroughly dried, worked with the pommel from head to 
tail, and oiled as before. 



CHAPTER CXVII. 

TALLOWED CALF-SKINS. 

A LARGE proportion of the calf-skins used are oiled, 
but those which are tallowed are less liable to be pene- 
trated by moisture. To prepare them, sprinkle the dry 
skins with water, scrape them with a dull knife or the 
stretching-iron, unless it is desirable to diminish their 
thickness by paring. Then pare down the head with 
the head-knife as far as the junction of the neck, 
flesh the body lightly, being careful to moisten the sur- 
face to prevent the knife entering too deeply. Dry the 
skins and pommel them upon the flesh side with a large 
pommel, and upon the grain with the cork instead of 
pumice stone. Tallow in the same manner as cow- 
skins, dry, then work under water, pommel and blacken 
twice ; after this operation pommel again, polish and rub 
upon the grain side with clear oil. A dozen of calf-skins 
weighing from 38 to 40 lbs. require from 12 to 15 lbs. of 
tallow. 

Harness-makers and saddlers use these skins for co- 
vering horse-collars, and for other purposes. They are 
also used for manuf\icturing thick shoes, and" to cover 
trunks, chairs, and tables. 



ENGLISH CALF-SKINS. 525 



CHAPTER CXYIII. 

ENGLISH CALF-SKINS. 

To prepare this kind of leather, choose the best kind 
of skins, and the process of manufacturing is similar to 
that employed for cow-skins intended for corresponding 
purposes. 

Tallow the skins upon the flesh side, but use only a 
small quantity of grease, so as not to penetrate the leather. 
This and the succeeding operations miist be very care- 
fully conducted, to avoid injuring or soiling the surface. 

The thinner skins are used for thin soles, while the 
thicker ones are curried white for the uppers of thick 
shoes. Formerly this white leather was used for heel- 
vangs. Moisten the skins slightly, pommel them in every 
direction, and after oiling and thoroughly cleaning, shave 
them down on the borders, pare from tail to head until 
soft, then pommel and scrape them with the round-knife, 
and pass over with the cork. During all these operations 
avoid scraping or scratching the surfaces, which are more 
liable to be injured than those of neat's leather. If the 
skins come from still-born calves, you avoid injuring 
them by passing them through tan liquor and exposing 
them for a time in the pits. 



526 CURRYING. 



CHAPTER CXIX. 

WAXED OALF-SKINS * 

Fleshing and Shaving. — In a preceding chapter we 
have given the best process for tanning calf-skins; we 
now give a description of the different processes to which 
the currier submits such tanned skins. 

Good dressers of waxed calf-skins have become in our 
day very rare. For about twenty years past the manu- 
facturers of patent leather have appropriated all the good 
workmen and have kept them busy, and since more is 
earned on patent leather than in dressing waxed calf- 
skins, the currier is almost the only workman left who 
carries his work mechanically and without principle. 

The English taught us to dress the skins which we . 
understood how to tan better than they. We have ex- 
celled them and now they are tributary to us, thanks to 
the improvements which we have made upon their les- 
sons. The Germans do as well with their glazed leather 
and dressing hides as we do, but in the manufacture of 
sole leather, waxed calf-skins, boot legs, and saddle 
leather we are far beyond them. 

For the first process use the plate knife, and to sharpen it 
proceed as follows : For this purpose use the finest sand- 
stone, which is long and round, and hold the knife turned 
to the back and inclined about two-thirds; to begin press 
upon it hard, taking care to turn the sand- stone every 
two or three minut«s in order to keep it even, which is 

* This process of manufacturing waxed calf-skins is extracted from 
"La Halle aux cuirs," Paris, 1864, and is the work of M. Ren6, one 
of the best Parisian curriers. 



WAXED CALF-SKINS. , 527 

essential in order to have the edge of the blade remain 
exactly regular. As soon as you reach an edge, assure 
yourself of it by holding it up to the light, when you 
notice a light feather which follows the whole length of 
the edge. Continue with the sandstone, but do not press 
hard, the mere weight of the hand and blade being suffi- 
cient. Then make two or three strokes upon the other 
side, and in five minutes the feather vanishes. When 
the edge upon the sandstone is gained, take the Scotch 
stone, which is the best of all the stones. It is an eight-cor- 
nered stone with a very sharp grain, and with it the edge 
can be burnished in ten minutes. The action upon this 
stone shows a new feather almost imperceptible to the 
eye, but you can feel it very plainly if you let your finger 
nail glide along the edge. This is removed in the same 
way as that which first appeared upon the sand-stone, 
taking care, however, to carry the knife lighter. When 
the feather has disappeared the edge feels smoother, and 
then you take the whetstone and proceed as before. In 
a very little while you obtain a smooth edge, and if, when, 
you run your nail along upon it, you feel its sharpness, 
and the nail meets no resistance, the edge is ready and 
can now be turned. 

In this operation proceed in the following manner : 
Cover the edge with tallow, take the plate of steel which 
must be carefully polished, and let yourself down upon 
your knees. Take the cross handle between your legs, 
incline the knife to the right and bring the steel to the 
edge; give the first stroke to the right, turn the knee 
slightly and give a second stroke, giving lighter strokes 
as you proceed, you come to the edge which turns under 
the pressure. You rest no longer upon the end than 
upon the middle to obtain a uniform edge, and if when 
you press the knees together you have raised the knife 



528 CURRYING. 

nearly perpendicular, you stop, for if you went on, you 
should fall and break out the edge, a fault of which many 
•workmen are guilty. 

In order to flesh and shave calf-skins, it is necessary 
that the edge should remain a little open, and especially 
that it is not set too strong, for it is better to' take off 
two shavings than one. The workmen who work with 
their edges set too strong, shave almost all their skins 
too hard, and when they come to the sides they often 
press deep into the leather. We have often seen how 
unmercifully skins were handled in this way, and ob- 
served also that workmen of this kind work with too 
open a grade and penetrate the skin against their will. 
A middling edge, not too open, is the best. 

Use the English beam, the surface of which is always 
very even lengthwise. Of this one must assure himself 
by using a very exact straight edge, for the least hollow, 
the smallest bunch, must be removed. Then look to 
breadth in the same way, and see whether it is exact. 
. This you ascertain by laying the back of the knife upon 
it. Move it up and down and observe whether it meets 
with any obstacle. The currying board must be rounded 
quite lightly and even at the edges. The thinner a skin 
is the evener must be the surface of the beam. The 
upright frame of the beam must be inclined towards the 
side of the workman at least two inches. 

After the instrument is well ground and set, and the 
board well prepared, proceed to flesh the calf-skin; and 
that the knife may not suffer by bits of tan, if such should 
remain sticking in the flesh side, have the skin well 
brushed upon the flesh and grain. Then take the skin 
and lay it crosswise upon the beam, a ravel in each hand, 
the tail piece toward you and the breast part hanging 
down. Begin upon the right side of the skin, give it a 



WAXED CALF-SKINS. ^ 529 

light blow with the sharpening steel to press it down, 
drive the knife into the flesh at the navel, and go down 
over it to the end of the breast points. Cleave only the 
flesh and preserve the membrane upon the skin every- 
where. Bring the skin from left to right, and give the 
second stroke. Go down as far as the arm will reach, in 
such a way as to cleave the flesh only, without cutting 
into the skin. When you come to the back lines, and 
especially to the skin- at the back of the neck, take good 
care to have the knife sharp, for since there is a stronger 
membrane in the lines of the back than in other parts, 
you might go in too deep and make a hole like an egg. 
We often see in the middle of a handsome calf-skin a 
defect like this, caused by an awkward workman. Go 
on with the work from left to right. Spread out the 
skin over the upper corners of the beam with great care, 
and hold it fast with the knees, so that it cannot move 
from its place in one direction or another, for the least 
displacement often damages the skin. 

When you have done here, turn the skin from right 
to left, and begin the work again at the right fore-leg. 
Move this twice in order to get around the joints, and 
to sever the nerves of the shank, which, since it is stronger 
than that of the sides, may make you commit a like fault 
to that mentioned above. Proceed with all possible 
caution to flesh the neck lengthwise, taking care to press 
sharply against the knife, and draw, or rather mow, the 
flesh ofl", but rest upon the knife only lightly. When you 
come to the breast or to the head, press on more in the 
stroke, bijt take only the flesh, and take no particular 
care to leave the skin smooth; this matter is attended to 
in finishing. 

When the calf-skin is well fleshed upon the neck and 
breast, turn it back to its former position, and treat the 
34 



530 CURRYING. 

tail part in the same style. In this way you finish the 
skin in three operations. Avoid forcing the strokes on 
the tail part, and everywhere mow off the flesh, and 
never double the stroke. By means of a little piece of 
steel preserve the sharpness and set of the blade. 

When the calf-skins are fleshed, hand them over to 
the grainer, who breaks the vein, stretches the skin out, 
works them, in a word, gives them the grain.- This 
process is useful, and it can be ma^e up for by nothing 
else : a calf-skin cannot be curried to perfection if it is 
not first grained with the grainer's wood. 

When the calf-skin is grained, take it again to the 
beam, and even off the throats and the cheeks. Feel 
carefully through them first so as not to make useless 
strokes in the same direction, and these strokes must 
cross each other in order to even off the head part well. 
When the head and breast are well evened, the object is 
accomplished. Fold the skin once and go over quite 
lightly with the shaving knife. For this purpose the 
back must be up. The cut goes straight, and do not rest 
or press upon the beam with the knife. It must be 
carried down quite naturally, but with a sure hand, 
taking off the rest of the flesh and bringing with it the 
bunches of flesh. We do not, however, approve of a style 
of finishing which takes off a great shaving, for by this 
the skin loses in weight. On this account have the calf- 
skin shaved over crosswise, very lightly only, but should 
it be necessary to manufacture them to sell by the dozen, 
take off all the thick places, even off the fore-shanks and 
the joints uniforml}^, take off one or two membranes 
from the sides, and also from the tail; in a word, you 
must use shoulder power, as one must if he will really 
complete his work. But we repeat that selling by weight 
has debased the hand of the workman, and he is com- 



WAXED CALF-SKINS. 531 

pelled to go over a calf-skin very lightly to preserve the 
vy^eight. Hence you shave the skin on both sides, then 
repeat the stroke on a quarter of the back. Everywhere 
the veins are shaved through a second time; the shoulder 
piece retains its strength, the extremities are spared, not 
the least unevenness nor the smallest cut is perceptible, 
and the calf-skin is curried as the necessities of the trade 
require. 

Before passing over to the process which is now fol- 
lowed, we shall make a few remarks in reference to cur- 
rying. In the majority of manufactories calf-skins are 
now no longer shaved transversely, but only lengthwise, 
and indeed it is done to save a few cents. In our opinion 
it is better to spend on a skin a little more and have it 
completely finished. 

We proceed now to the finishing, which is called by 
the trade tl^e setting out, or the settling to the wind. 
This process is the most important of all table work, and 
it is likewise the most neglected, for routine has taken 
the place of the knowledge of our first teachers. 

In finishing, bring the shaved calf-skins together in a 
tub with weak liquor, if you have any ready, or in clean, 
pure water. It is well, if there is time, to have them 
rinsed in this water at least 24 hours; then they are 
taken out and laid with sides turned in, rolled up or set 
to the wind in a cask in a circle around it and in the 
middle. It is better to full quite a quantity of skins to- 
gether, for thereby we reach a better result than if taken 
singly. Pour into the cask two or three pails of water 
of weak liquor, then each workman takes a pounder and 
begins in time with the next, to pound the skins in the 
tub. The strokes should never be repeated in the same 
place. In this Avay the calf-skins are sufficiently fulled 
in seven or eight minutes, upon one side. Turn them 



532 CURRTING. 

about, and the work begins again and goes on till they 
fall down, or are fulled as soft as a rag. 

In the great workshops where mechanical power is 
used, there must be a fulling cask. The calf-skins are 
brought to it, bent into a muff form, the proper quantity 
of water or tanning liquor is poured in, and the cask is 
made to revolve. Thus- the skins full and cleanse them- 
selves. By this much hand work is saved, and the work 
is better, for they are allowed to full the necessary length 
of time to become perfectly tender; while in fulling by 
hand, the workmen, to whom the business is not specially 
pleasant, perform it negligently, which is a great fault, 
since a bad calf-skin fulled before the setting out is almost 
like a dry skin which one should put into the pit before 
it is prepared for the tanning process. Before the table 
workman can become master of his skin, he must soften 
it thoroughly again, and it should be half cleansed, that 
the nerve may be broken. By this the work will be 
forwarded; but this process is often slighted, especially 
in piece work, and hence we would advise that it be per- 
formed by mechanical means whenever possible. When 
this work is done, rinse the skins in clear water or in 
weak ooze. Pure water is preferred. 

The tools used in the table work are the scouring- 
stone, the smoothing-iron or sleeker, and the scouring- 
brush. These tools being well known, we do not think 
it necessary to describe their form and appearance. 
AYhen the tools are put into shape, take a calf-skin 
from the cask where it has been soaking, and place it 
upon the marble, the flesh side up, the tail part turned 
to the right, and the whole hinder portion of the skin 
upon the marble, and the neck four inches from the edge. 

Take the sleeker and go to work on the back strips, 
make the first stroke in the direction of the tail, beginning 



WAXED CALF-SKINS. 533 

at the shoulders, and the second stroke proceeds from 
the same centre, and is directed straight along the neck 
between the ears. If by both these strokes the calf-skins 
are not smoothed down flat along the back, repeat them, 
and begin them upon the throat almost transversely. 
Leave the fore shanks and turn to the tail part of the 
calf-skin. The strokes from the shoulders begin along 
the back and go on one after another, taking in an 
inch to an inch and a half in width, and from twenty to 
twenty-four inches in length, at every stroke, till you 
come to the navel. The purpose of this operation is to 
free the neck and other parts from superfluous thickness. 
First of all, endeavor to even the skin well and to make 
the thickness as uniform as possible, and to gain this end 
begin with the fulling of your leather by the first work- 
ing, which is the stretching of the flesh side. 

When the neck part is well evened and the rear part 
well beaten, stretch the skin as much as you can, since 
the more you extend it the thinner will the skin become 
on each side. The fore shanks are stretched and evened 
by themselves. Then repeat the strokes upon the tail 
part, pressing hard upon the roots of the tail and upon 
the rear of the skin, and when you come to the hind 
shanks trim these by oblique cuts right and left. After 
this, gather up all the cuttings, take the brush, dip it 
in water, and wash ofl^ clean the flesh side of the skin. 
Now turn it about in order to use the iron upon the other 
side, proceeding as before. Then fold the skin square, 
and rinse it out in clean water. 

Take the calf-skin again and spread it out upon the 
marble just as you did in working the flesh side ; take the 
scouring-stone and stretch the skin, going down from the 
shoulders along the back to the tail. Then turn around 
and stretch it in the direction of the neck, always along 



f 

534 CURRYING. 

the back — stretching it with all your force. If the calf- 
skin possesses too much nerve, do not hesitate to cover 
the marble with a thin coating of tallow, so that there 
may be no displacement of the skin at this point. After 
this is done, begin upon the neck, pressing the stone 
upon it hard without holding it too fast in the hands. 
The weight of the fore part of the body is enough, for if 
you hold the stone too firmly, your hands become tired 
too soon, and as you go to and fro with the strokes let 
the stone slide along easily over the skin to clear off the 
grain. When you repeat the stroke, lean upon the tool, 
but do not press hard upon it, for strength would be 
wasted to no purpose. 

When the neck is well stretched, turn back again in 
the direction of the rear of the skin, and beginning the 
strokes at the shoulders, work down, taking about li 
inch at every stroke towards the navel. You come to 
the breast part, which you work by straight strokes from 
you, taking off' the superfluous leather which appears 
here. The fore shanks you stretch by cuts right and 
left. Then take the tail part, which you press as hard 
as you can, for this, part, always full of nerve, must be 
worked down at any cost. Then stretch the belly and 
carefully work down the hind shanks. When this is 
done, take the brush and carefully wash the grain side 
with it, and take the scouring-stone again, letting it play 
at pleasure over the skin. The drier the operation be- 
comes, the more the grain is compressed. All the 
veins must vanish, and the lines show themselves upon 
the epidermis. It is only when you perceive this that 
you can regard your skin as sufficiently dressed. Then 
take your brush, wash the grain again, and use the 
smoothing-iron, the blade of which must be in good order, 
in order to avoid a change in the grain. Use your 



WAXED CALF-SKINS. 535 

sleeker in the way you did your scou ring-stone, only seize 
it firmer in the hands, so that it will not hop, and do 
not touch it to the grain in the back stroke. We have 
seen workmen who neglected to press the skin with the 
stone, and sought to make the veins disappear by stretch- 
ing the skin by strength of arm alone, and they did j but 
when their skin came upon the marble, the veins ap- 
peared again, and showed their work to be incomplete. 
The scouring-stone alone can take out the veins, the 
stretching comes after it, but cannot take its place. 

When the calf-skin is well pressed and stretched, turn 
it around and begin the work on the other side in the 
same way. Take good care always to have the back 
strips well stretched, for the least displacement will 
cause the skin to be stretched crosswise and you should 
be obliged to full it over again. 

After exposure to the wind, come the stiffening and 
drying. In summer, after calf-skins have been thoroughly 
exposed to the wind, they may be oiled without being 
dried, but in winter it is advisable to have them dried, 
especially the skins of males. In large establishments, 
there should be a hydraulic press for that purpose, and 
the operation can be done successfully by that means, 
but in ordinary establishments, where machinery is lack- 
ing, the skins should be exposed to the air until the 
moisture has completely evaporated. This greatly facili- 
tates the workmen's tasks, the skins tend better, and the 
action of the stretching-iron is much stronger, and the 
veins do not rise; besides, the skin will be more compact. 
Male calf-skins especially require much care, chiefly in 
the necks, the flanks, and the edge of the rump ; to these 
portions an intelligent workman should devote all his 
skill. 

In stuffing the skins, use in summer a substance com- 



536 CURRYING. 

posed of white whale oil, tallow, melted by the fire, and, 
in order to combine these to the fattj bodies, add a third, 
by mixing with them a little degras of the best quality, 
in the proportion of one-fifth of degras to four-fifths of 
other matter. 

In winter, in the place of whale oil, use cod-liver oil, 
and try as far as possible to procure the cod-liver oil 
entirely pure, free from any admixture of vegetable oil. 
In general, all animal grease may be used to oil skins. 
Such is not the case, however, with vegetable oils. Not 
only do they not impart any body to the material, but 
they also give it no softness, and they are always apt to 
escape from the tissue of the skin, either on the flesh side 
by rising to the surface, or on the grain side by raising 
to the epidermis, forcing often little blisters which burn 
the grain or brown it. 

When the skin has been well dressed and stretched 
upon the marble table, after every vein has disappeared, 
coat the grain side slightly, then fold the skin and leave 
it two or three days in this position before oiling the 
flesh side. The grain returns to its original nature 
under the wholesome influence of this application, which 
penetrates and spreads slowly through the tissues of the 
skin, and in three days the entire coating of oil will have 
penetrated all the pores of the skin, the tallow alone 
remaining in a paste on the surface, and serving to keep 
it fresh, when the skin is ready to be exposed to the air 
or heat to dry it. 

If you should have smeared the flesh side with oil 
immediately after the operation of stufling the grain, the 
workman who applied the oil, in pressing the skin to 
m&ke it stick, would drive out all the oil by the pressure 
of the stretching-iron, and there would not remain matter 
enough on the grain side to soften it, or to preserve it 



WAXED CALF-SKINS. 537 

from the too strong action of the air or the heat of the 
drying stove, and thus the object would not be attained, 
for we aim above all things at securing a soft, pliant, and 
mellow grain. In order that this end may be entirely 
secured, the grain must have been thoroughly saturated 
with tannin during the tanning, and this desirable result 
could not possibly be attained in cnlf-skins, when the 
tanning of the grain has been neglected. After the calf- 
skins have remained two or three days oiled on the grain 
side, you make preparations to oil them on the flesh side, 
and to effect this operation, which is one of the most 
essential in the preparation of calf-skins, operate in the 
following manner. 

In its composition, use as far as possible only degras 
of the best quality. Sheep or buffalo is to be preferred ; 
it is more penetrating and it leaves less deposit upon the 
skin. Both in summer and also in winter, add to it a 
certain quantity of good tallow, and in mixing it do not 
melt all the degras. Out of 440 lbs. of degras you melt 
about 110 lbs. You have it melted in a pot until it 
almost boils, then pour it gently upon the rest. Next 
you melt a potful of tallow, which you pour out at the 
same degree of heat, and you mix it together briskly by 
means of a stick. 

When the mixture is nearly complete, take a stirring- 
pole and keep on stirring the contents until it is nearly 
cold, so that the substance may be so intimately mixed 
that the part of the separate ingredients will not appear. 
In summer, when it is warm, double the quantity of tal- 
low, but in winter graduate this according to the tem- 
perature. Sometimes by drying with a stove it happens 
that you use as much tallow as in summer, so that the 
stuffing be made compact and not run after it has been 
applied. 



538 CURRYING. 

This being done, take the skin by the two hinder 
shanks and lay it on the marble table as far as the 
shoulders. Feel the rumps and the shanks to assure 
yourself of their strength. Press it slightly upon the 
marble, without using too great an effort, so as not to 
displace the leather and in order not to remove the matter 
applied to the grain side. Take a smearing cork covered 
with smooth lamb-skin, or rather a soft brush, and dip 
it into the degras, which stands on a corner of the 
table within reach. Take up a certain quantity and 
apply it to the left buttock of the skin, then the same 
on the right buttock, and spread it uniformly all over. 
Cross the sweeps so that the coating may be every- 
where equal, taking care to go softly over the grain, then 
pass the brush from one flank to the other and from the 
edges of the rump to the shoulder. After doing this, 
apply a fresh coating to the nerves of the hinder shank, 
to the rump, the centre, and borders of the belly. The 
skins being thoroughly tanned and having neither lime 
nor moisture will stand an enormous quantity, and you 
lay on a coating almost equal in thickness to the leather 
itself. The males, after their rumps have been well 
smeared, should have a uniform coating, their buttocks 
being as thick as the borders, but with the females it is 
different, the borders of their rumps and their flanks are 
thinner, and treat them accordingly. The centre of 
these skins being thicker and more compact than in the 
male skins, make repeated applications to those . parts 
until at least one-third more is added. 

All the ^arts being now placed on the marble, take the 
skin on the right side of the fore and hind shanks, and 
turn it round briskly. Then seize the two breast points 
and spread the skin out smooth. Take the stretching- 
iron and press down the neck gently so as not to change 



WAXED CALF-SKINS. 539 

its shape, for were you to press it violently, the action of 
the stretching-iron would displace the skin, and you 
would have much trouble in readjusting it. and making 
it as straight as it was. And even then you would not 
succeed so far as to avoid leaving wrinkles about the 
neck, which is a common defect among workmen in 
applying oil to calf-skins. Many do not know how to 
adjust a skin correctly, and nothing is more ugly than a 
finished calf-skin that has wrinkles on the neck, com- 
mencing at the shoulder, when spread out on a table. 

To resume, the calf-skin lies down flat without requir- 
ing effort to put it so, as it has been already stretched 
and made even. Apply the degras to the thick part of 
the neck, then spread it out and equalize it. Next, lay 
another coating on the neck according to its thickness, 
and use more in proportion on the nerve of the fore 
shank, the brisket and the shoulder ; but give great care 
to the sides of the neck, for a calf-skin impregnated with 
oil about the neck is very ugly. 

Nothing more unmistakably indicates an inexperi- 
enced oiler than a skin that spreads unevenly and shows 
oil through the neck and shanks. After this is finished, 
take a little stick, which pass through the holes that you 
have taken care to make in the hinder shanks, and leave 
the skin to dry. You use about 6 lbs. of degras to smear 
50 lbs. of calf-skins, when taken out of the pit on the 
flesh side ; and about 1 h lb. to smear the same quantity 
on the grain side. 

The drying of oiled calf-skins requires the greatest 
care. In winter, when the temperature is low and the 
air moist, calfskins cannot be dried in the open air, for the 
degras would remain on the skin, the flesh side would 
mould, making spots, and the color would be hideous. 
Recourse must be had, therefore, to the drying stove, but 



540 CURRYING. 

in this case the heat should be temperate. Too much fire 
is to be avoided, for with calf-skins freshly oiled, the 
greasy matter would decompose and run, and as calf- 
skins are suspended by the rumps, and as this portion 
receives twice as much degras as the neck which hangs 
down below, the result would be that in running from 
the rump downwards, the grease would penetrate the 
neck to the detriment of the body of the skin, which 
would not be supplied with enough grease. From 86 to 
100° of heat will be sufficient. With such a temperature 
Paris-slaughtered calf-skins, oiled and fresh from the 
pits, can be dried in eight days. A drying room should 
have one or more apertures in order to carry off the 
moisture that escapes from the skins, and thus the drying 
is better and more promptly effected. 

When the calf-skins are entirely dry stretch them out, 
and have them piled for twenty-four hours; then bring 
them again into the air, where you leave them three, 
four, or five days before piling them up again. The 
freshness of the atmosphere spreads itself upon the skins, 
and restores to them that suppleness which cannot be 
gained when dried in a heated room. Their weight in- 
creases ; they are easier to bleach, and the flesh becomes 
easier to cut. At the end of three, four, or five days, 
pile them up again, folded together, having the flesh side 
inwards. Stretch out the edges and hams carefully, so 
that no folds may be -made by pressure ; then load them 
with weights as heavily as you can, and leave them thus 
for eight days at least. 

In regard to drying in spring time it regulates itself, 
and no other precautions are necessary except to change 
the places of the skins every now and then, and to pile 
them up as they become dry. 

In summer, when the heat is excessive, precautions 



WAXED CALF-SKINS. 541 

must be taken. We have seen some calf-skins dried in 
twelve hours, but the Jflesh side was streaked like marble, 
and the flanks burned by the heat. In bleaching fhose 
skins the dust flew up before the scraping-iron. Often 
the greatest trouble is experienced in restoring them to 
their proper degree of drying heat. The best method 
when that happens is to pile the skins up in a cellar or 
other damp place, and leave them there eight days with- 
out changing the pile. At the end of that time bring 
them up out of the cellar, and pile them in the ware- 
house, where you leave th-em as long as you can in oil. 
Thus, the flesh side becomes equalized, and the coating 
of tallow, remaining on the flesh, combines intimately 
with it. When they are handed to the bleacher they 
cut -well, and the difficulty is thus removed, although 
not without a loss in weight. 

The season most propitious for perfect success in oiling 
is during the months of September and October, the 
heat being then temperate during the day ; the nights 
are cool; the process of drying goes forward slowly and 
surely ; the material retains its suppleness and weight ; 
it is easily finished, and the quality is perfect. 

After the skins have laid the proper length of time, 
clear them of fat upon the flesh and grain sides. For 
this purpose use a small stretching iron, not pliant, which 
you whet upon the sandstone till it is tolerably sharp, 
but do not bend around its edges for reasons which we 
will indicate. Lay the calf-skin lengthwise upon the 
marble table, and press heavily upon the iron, which is 
half bent towards the body ; the strokes are given in the 
same direction you took before you oiled the skins; smooth 
out carefully the folds which sometimes appear along the 
edges. Take good care not to open the flanks, and those 
parts of the skins which have been worked together, so 



542 CURRYING. 

as not to disfigure the skin. This would be an evil that 
could hardly be obviated, as all the disfigured parts lie in 
foldf? and wrinkles, and can never be made even again. 
How often have we seen calf-skins cleared of fat by in- 
competent workmen in such a way that the finisher 
could never restore them to a good condition. He lost 
time and lessened the weight of the goods in the effort, 
but gained nothing. Therefore, watch this process to 
avoid the above-mentioned bad result, and do not bend 
up the edge of the instrument used in the operation, so 
that you can give the stroke according to your liking, 
and avoid making useless notches in your skins. If you 
wish to shave the calf-skins, take the folds out of them 
lightly and gently with a blunt sleeker. 

Bleaching or Whitening. 

The bleaching of waxed calf-skins is one of the most 
essential processes in its manufacture. It is the beginning 
of the end, and the defects of the bleacher will be no- 
ticeable by all, even by inferior judges. A streaked calf- 
skin attracts attention, and an ill-finished flesh side can- 
not be kept out of sight. Any slight cut should be 
made to disappear; if not, it will remain as a defect, 
exposed to the view of the buyer. Therefore, to make a 
good bleacher, a man needs to be skilful and intelligent 
at the same time, otherwise, he will be unable to turn 
out a perfect article. 

The manufacture of waxed calf-skins in France became 
so largely developed in the years subsequent to 1830, 
that workmen capable of performing the bleaching pro- 
cess with the knife could not be taught fast enough. 
Another motive, and one equally powerful, the sale of 
calf-skins by weight, forced the manufacturers to look 
to it. 



WAXED CALF-SKINS. 543 

The manufacturers of the Loire-Inferieure, the Nantes 
tanners were the first to meet with these difficulties. 
Some worl^men who did not like over much to 'whet 
their tools, and who were required to clean their skins 
when green, thought fit to set the edges of their stretch, 
ing-iron bluntly, and, not satisfied with removing the dirt 
from the skins, they also took off the small morsel of 
flesh remaining. The better instructed perceived this 
and sought to draw advantage from this nascent inven- 
tion. They bought good blades made of steel, which 
were carefully ground, and the edge curved conversel3\ 
With a fine butcher's steel the edge was set, and the 
workmen began to scrape properly. By degrees the 
more expert among the workmen got their hands used 
to this, and the process of bleaching with the stretching- 
iron became improved. Necessity, the great mother of 
invention, did not fail the seekers in this respect. 
Bleachers with the knife gained auxiliaries, and orders 
were no longer delayed in the filling through the lack of 
competent workmen. When a stretching-iron is wielded 
by a skilful and intelligent operator, it may be made to 
take the place of the knife ; better than this, calf-skins 
are less put out of shape and better prepared by being 
bleached with a stretching-iron. But how few workmen 
combine the requisite qualifications, and how many 
among those who possess them will not give themselves 
the trouble to do it well ? 

In order to bleach a calf-skin well with the stretching- 
iron, it must first be worked lengthwise and then gone 
over transversely with care, working without interrup- 
tion, removing the veins and knots of flesh, and especially 
the cuts, at least those which can be made to disappear. 
By taking all these precautions, a skin is often turned 



544 CURRYING. 

out tliat ranks in the first quality, otherwise some have 
ranked only as second rate. 

The cost of the operation of bleaching with the knife, 
for medium-sized Paris-slaughtered calf-skins, amounts to 
forty cents per dozen, and of bleaching the same skins 
with the stretching-iron to thirty-five cents per dozen. 
It is to be understood that for this price the workman 
should remove all such defects as can be made to dis- 
appear — in fact, he should put his calf-shins in full dress. 

The skins that are finished up with the shaving-knife, 
although they are cleared of fat before the process, cannot 
be grained without being gone over a second time. The 
reason of this is that the corners of the beam in shaving 
often make impressions upon the skin which subsequent 
operations cannot remove, and these marks injure the 
looks of the skin. After this, we advise the following 
means : Take a light brass grainer, round off its corners 
well, and put it first upon the sandstone, then upon the 
English stone till it is polished almost as bright as a 
mirror, then take the skins crosswise as in the working 
in. In order to avoid making wrinkles, remove all irre- 
gularities from the board, stretch the necks and flanks 
straight, take ofi" and even the folds which have appeared 
in drying. Remove, by a single strong pressure, the veins 
which withstood the stretching process, or which have 
appeared since that. This operation makes the grain 
remarkably pliable and uniform. Then take a pushing- 
iron, not too pliable, make its edges very smooth, so that 
it will not be apt to gnaw in or make furrows. Begin 
now at the neck to clear the skin and to compress it. 
Take special care to avoid scratches, w^hich give to the 
grain a marbled look and injure the whole of the curry- 
ing work. This important operation is too often put 
into unskilful hands, and is executed very badly. Many 



WAXED CALF-SKINS. 545 

manufacturers attach little importance to it, but we think 
it is best to devote to it great attention. First, it imparts 
to the grain a greater softness, while it also strengthens 
the fibres of the hide. You prepare the way for giving 
a grain to the skin, and with a skin prepared in this way 
beforehand one is sure of a grain of fine appearance. It 
is very difiicult to grain a fine calf-skin alike in all parts 
if this operation has not been first performed. 

In the same way treat calf-skins that have been whit- 
ened with the knife for that purpose, and such as have 
been entirely cleared of fat before whitening. The tallow 
which remains upon the grain hardens and equalizes 
itself under this operation of dry finishing. The grain 
will again become pliable and free, and often calf-skins 
that have been too quickly dried or rather bathed in the 
drying-room, or in the~air in summer heat, are restored 
and made very soft. It is this way of working by which 
one gets that pearly yet tender grain, which to the com- 
mon eye is a sign of fine work. 

Graining. — There are several ways of graining calf- 
skins. Almost every manufacturer has a peculiar method. 
Some make a cross grain by taking their skins from the 
four quarters ; this is the English method. Others make 
a barley grain, and in our opinion this grain is the hand- 
somest, for it breaks the skin less and spares the flanks 
more. Others start it from the four quarters and end it 
by running straight from head to tail, which produces 
a very fine grain, but it can only be done successfully 
with female skins that have been very compactly tanned, 
and would not do for male calf-skins. 

In order to grain a skin well one requires to be prac- 
tically acquainted with skins so as to be able to judge at 
the first glance of the quality of the skin to be grained, 
for if a calf-skin is firm and compact, it can be dressed 
35 



546 CURRYING. 

with cork without danger, and without fear of bringing ' 
too coarse a grain to the surface. But this is not the case 
with calf-skins that are a little flabby ; their grain is 
tender, and they should be treated carefully or the grain 
surface will rise so that it will seem to be detached from 
the fibres. 

This is the way to proceed in this operation : Take a 
grainer not over 62^ inches in breadth, and covered uni- 
formly with cork. The grain should not be too convex, 
and should form an elliptical arch, and its length may 
vary from 10 to 11 inches. In the centre have a band 
of leather at the back, broad and soft so as not to hurt 
or fatigue the hand. This instrument should be very 
light and easy of use, as it is almost always worked with 
one hand, and this hand would soon'become fatigued if 
the instrument were not of this condition as to its light- 
ness and adaptability to the hand. Take the skin by 
the left shank and roll this shank closely until you come 
to the navel, so as to fix the direction of the grain that 
you wish to produce, starting from the left brisket to the 
right hinder shank. If the skin is firm, pass the cork, 
holding it by the right hand, under the left^ and bear 
down heavily with both hands, taking care to follow the 
corners of the cork, which is essential to curve the grain, 
for if you draw it straight the grain will remain flat. 
You follow up without interval, taking care to push 
from left to right only a distance equal to one-quarter 
of the breadth of the cork in order to produce a uniform 
grain. When you reach the right flank, do not crush it, 
but pass lightly over it, pressing only lightly on your 
cork until you reach the hinder shank, when you press 
heavily. 

The grain being well brought out through the whole 
length, unroll the skin and continue, passing carefully 



WAXED CALF-SKINS. 547 

over the left flank, and pressing heavily upon the rump, 
for the grain of this part does not develop itself as easily 
as elsewhere, and often a double amount of work is re- 
quired there. Still bringing out your skin, you arrive 
in this manner at the end of the shank, then you turn 
the skin around to work on the neck. This part you 
also roll and begin your grain again in the middle where 
the other commenced ; there you proceed in the same 
manner, going carefully over the weak parts and press- 
ing heavily upon the neck in order to break it down. 
When you reach the extremity, take the skin straight 
before you and roll up all the throat and neck with the 
left hand, thus reaching to the middle of the skin, there 
hold it rolled up with the left hand, while with the right 
you curve the grain lengthwise in a uniform manner. 

Mode of making the Blacking and its Applications. 

The blacking is made in the following manner : Take 
good light lampblack and let it soak in linseed oil for 
several hours. If you wish to make a quantity of black- 
ing, put in one-tenth lampblack, which gives a beau- 
tiful color and does not dirty the brush. After it is well 
saturated in a small quantity of oil, crush it to mash the 
lumps either \vith the hands or upon a marble slab with 
a roller prepared for the purpose. When it becomes of 
the consistency of paste, and after all the lumps have 
disappeared, pour oil upon it and mix slowly. In winter 
mix in linseed oil, but in summer put one-half cod-liver 
oil, as the linseed oil penetrates and spots the skin. To 
this mixture of lampblack and oil add an ox-gall and 
five quarts of beer black, or ru^t black, or bark prepared 
with logwood, verdigris, gall-nuts, and gum Arabic. This 
last black is very handsome, and gives a magnificent 
blue-black basis. After the whole has been well mixed, 



548 CUERTING. 

making a solid paste, next melt of the tallow twice the 
weight of the lampblack in winter. You only melt it, 
and do not let it become too much heated, for if boiled 
it would coagulate and make little lumps when poured 
out. It is sufficient to simply melt the tallow before 
pouring it off, and as soon as it is poured it should be 
vigorously mixed. By this method the blacking will 
always turn out well. In summer use three times as 
much tallow as blacking, and we have known manufac- 
turers who added yellow wax with a very good result, 
especially in small calf-skins, as this often imparts a 
certain appearance of solidity to the flanks which in- 
creases the general effect to the eye. 

Let the blacking become thoroughly cold before using 
it. Take a dozen skins, and place the largest under- 
most, arranging them on the table so as to black them 
rapidly and avoid any marks being made by the brush. 
Lay all the skins with the flesh side uppermost, as a 
matter of course, and the whole rump part as far as the 
forepaw, so that in turning the skin around you may 
only have a small part of the neck still to black. Hav- 
ing done this, take your blacking-brush, which is of the 
shape of a mushroom upside down. Take it in the right 
hand and dip it evenly in the blacking, taking care, 
however, to use only a small quantity. Place it on the 
rump and rub the flesh briskly, sweeping the brush angu- 
larly, so as to apply it thoroughly, and use the left hand 
at the same time as the right to increase the pressure. The 
strokes are made from the rump towards the neck, and 
when you reach that part the brush is almost dry. In 
order to avoid penetrating that part, which is always 
weaker than the rump, pass at once carefully to the bor- 
ders, where you use very little blacking. Take care not 
to let the brush touch the under sides of the borders, so as 



WAXED CALF-SKINS. 549 

not to leave any spots of blacking, for the reason that the 
skins may be kept clean for the subsequent process and that 
you may. not have to clean them with the stretching-iron. 

After the skin has become quite black, rub your brush 
dry to remove the dirt, and even leave the brush and rub 
with the hand so as to roll all the small lumps, and, 
after the blacking has dried' thoroughly, take a horse- 
hair broom and sweep them off at the skin. When this 
operation is well done, the finger may be applied almost 
without being blackened by the contact. This is the 
way to see whether a skin is well blacked. Having 
finished the rump, turn the skin round, and lay upon the 
left hand edges of the skin remaining upon the table a 
piece of leather or pasteboard, so as to prevent the 
blacking, upon the edges of the other skins, from staining 
the grain of the skin which you turn, after which you 
black the neck in the same manner as the rump. 

A fault of many blackers is, that they spread the 
blacking without brushing it in enough. This is more 
rapid but not as good, for often in sizing the skin for 
the first time, the brush raises the flesh and the skins 
turn out gray instead of black ; and even when the skins 
are quite smooth, the flesh remains reddish in color, 
which becomes apparent when they are sized for the last 
time, but then it is too late to remedy the evil. 

A good blacker is a valuable workman, for when a 
skin is too pale after having been oiled, he will darken 
its color ; if it should be too much saturated, he will also 
skilfully avoid adding to this. This operation, therefore, 
requires an experienced man, one thoroughly acquainted 
with his task. For medium Paris-slaughtered calf-skins 
this process costs eighteen or twenty cents per dozen, 
for an active expert workman cannot get through more 
than from five to six dozen per day. 



550 CURRYING. 

Finishing. 

Prepare your wax in the following manner : Take 
some cuttings of glovers' skins (these parings should be 
kid, we prefer such to all others, for goat-skins will give 
a much finer glue, and consequently it will be easier to 
use), and let these parings soak in water during twelve 
hours, then rinse them well so that no foreign substance 
may remain with them. 

If you wish to make three pounds of gelatine, take 
one pound of these cuttings and boil them in five quarts 
of water. Skim off the first boiling carefully, and then 
let it boil for about three hours over a slow fire. At the 
end of that time strain it through a cloth, and let the 
liquid cool down. By this means you obtain a tender 
gelatine, which breaks easily. It should not be too 
strong, for it would then break with difficulty, and as 
you mix it with tallow it would not mix readily, if it 
was too hard, and it will be difficult to employ. More- 
over, if the gelatine were too strong, it would prevent 
the polishing process, and the calf-skins will be streaked. 

The great fault of many finishers is in using a first 
glue of too strong a consistency. 

Therefore take, according as you may need, say two 
lbs. and one-fifth of the gelatine, which you break up 
by means of a piece of wood kept for this purpose, and 
you crush it during ten minutes; then take II lb. of 
tallow melted by boiling. Crush this tallow thoroughly, 
and, in order to make it more 'pasty, mix with it about 
3 J ounces of linseed oil in summer, and 7 ounces in 
winter ; for when the temperature is low tallow hardens, 
and this quantity of oil is necessary to render it more 
easy of handling. 

When the tallow is well crushed, mix it by degrees 



WAXED CALF-SKINS. 551 

with the gelatine forming one substance of the two; this 
mixture should be made with much care. 

Use in preference to other sorts, good beef tallow, and 
have it always melted by boiling. It is preferable to 
mutton tallow, which is too dry, and always more diffi- 
cult to crush than beef tallow. Never use decomposed 
size, for it always gives the worst results. The material 
being well mixed take a soft brush, so that it will not 
streak. Place a skin on the table, and brush it with a 
hand-brush lightly, to rid it of any dust or pellets of 
waxing that may adhere to it still ; then with the size 
brush spread the skin over with the first sizing, using a 
small quantity for the females, and a larger quantity for 
the males. With the latter, take especial care to cover 
the flanks well, and especially the necks of those that 
are old. Equalize the whole by a last light brushing, 
and then turn the skin over, and go through a like ope- 
ration on the other side. 

Having done this, hang up the skin to a wooden bar 
with hooks, by a little hole made in the centre of the 
throat. 

Let each skin hang in summer only during the time 
that it takes to size four skins, and in winter while you 
are doing six. Do not let the size dry longer than this, 
for it would be too difficult to polish. Therefore, un- 
hook the skins as you go on, and pile them up on the 
trestles. 

After the first coating of size has been given to all the 
skins, prepare to polish them ; and, for this purpose turn 
the pile of skins upside down, so that those first polished 
may be those that are first sized. 

For this operation a very smooth polishing surface is 
necessary, for that no straps may be made. Polishing 
may be done upon smooth marble, or upon a table of 



552 CURRYING. 

walnut wood, and many are polished upon a foundation 
of leather. When the skins are large, and too much 
charged with oil, it is better to polish them upon marble. 

If the skins are medium sized and in the same condi- 
tion, polish them upon a walnut table; but if you have 
small skins or skins that are too full, it is better to 
polish them upon a foundation of leather, and take care 
to spread a little talc upon this basis from time to time, 
so that the skin may slide over it easily, and not stick, 
thus avoiding any crisping in the polishing process. 

Polish all the skins transversely and often ; when you 
find skins which do not polish easily, work them length- 
wise and crosswise. Always begin at the neck, and 
make the strokes consecutive, avoiding any crisping or 
marks that will remain and appear at the last sizing. 

If the skins are not oily, you need not fear to darken 
them, and polish them vigorously ; but if, on the con- 
trary, they are brown already, you pass over them as 
lightly as possible, so as to avoid darkening their color 
still more. 

These two operations require great care and cleanliness. 
Before turning the skin over to give it the first sizing ; 
take care to wipe the table with a woollen rag to remove 
the marks of the brush which, after the skin is turned, 
would soil the flesh side, and oblige you to scrape it 
dean with the stretching-iron, which would leave ugly 
traces on the grain side of the skins. 

- Pursue the same plan in polishing ; and in this manner 
the skins are always scrupulously clean on the flesh side; 
and in our opinion these are precautions that should not 
be neglected, for a skin spotted on the flesh side always 
denotes a careless workman. 

After these two operations are finished, you prepare 
to give your skins their last sizing. This size is made 



WAXED CALF-SKINS. 553 

up in the following manner : First melt your gelatine, 
then add a quart of water to reduce its strength, and let 
it cool off. Next crush it with the size-beater, and mix 
in a little black soap, and 3 J ounces of tallow to each 
pound of gelatine. Then add about a quart of size in 
paste with the addition of a little linseed oil to render 
it more easy to dry, and mix the whole mass together 
with great care. Thanks to this composition, you pro- 
duce a fine lustreless size, which is the most agreeable 
to the eye and the most advantageous, for it conceals all 
small defects. 

But if you wish to obtain a finer and cleaner size, you 
set about it in this manner : Dissolve in water some 
white or black soap (white soap is preferable), and let it 
boil thoroughly, so that the soap may be perfectly dis- 
solved, then put in your pound of gelatine, which dissolves 
at once, and while the whole is boiling gently, stir about 
7 ounces of size paste into a quart of water in a separate 
vessel. When this has mixed well pour it into the first 
vessel and let the whole boil together thoroughly. Skim 
it carefully, and at the end of ten minutes take the size 
off the fire, strain it through a cloth and leave it to cool, 
taking care to stir it from time to time until it acquires 
the desired consistency. After it is quite cool crush it, 
and, without adding anything further, you are ready to 
give the skins their last sizing. This size is very fine but 
rather light. 

Lustreless size is properly appreciated both in France 
and this country. The English do not like calf-skins 
sized according to the French process, and they bring 
their calf-skins white and all ready to be waxed. In 
waxing and sizing them according to their method, they 
generally wax them with very light wax, and size them 
with a size much more solid than the above, but their size 



554 . CURRYING. 

has this defect, that it turns gray with age. In putting 
on the last size make use of a very fine sponge ; dip it in 
water, and then squeeze it strongly so that the least pos- 
sible mixture may remain in it. Take the skin and 
spread it out on the table with the rump towards you, 
then seize the sponge and take a quantity of size in pro- 
portion to the dimension of the skin. Dip the sponge as 
deep as possible into the size and draw it briskly towards 
the rupip, then work it right and left to spread the size, 
and smooth the whole, commencing at the edges of the 
rump and the hinder paws. Follow your sweeps quickly, 
advancing towards the neck, pulling the skin by the tail 
with the left hand ; as the right hand advances, the left 
descends, and thus you reach the neck transversely, of 
course. By this method you rarely spill any of the size. 
The first dip fills the sponge, and this suffices for the 
whole skin. Then hook it up to the bar and leave it to 
dry for at least twelve hours. This operation should take 
place in a room where 'neither steam nor dampness can 
penetrate, for either of these influences would tarnish the 
size, and in certain cases where the skins are put together 
by dozens, they would stick the one to the other, and, 
the goods would at the same time lose in appearance 
and value. 

These precautions are especially necessary when the 
skins are destined to be exported to a long distance ; for 
a case of calf-skins that comes to hand glued together is 
greatly depreciated. For this reason, in goods manufac- 
tured for exportation, too much care cannot be taken to 
allow the size to dry thoroughly. Twenty-four hours are 
often necessary, especially in winter and in foggy weather, 
when the air is overcharged with moisture. At such 
times the rooms in which the skins are placed to dry 
should be heated from 60° to 70° and carefully ventilated, 



WAXED CALF-SKINS. 555 

SO that no steam may remain to condense and adhere to 
the size, which would scarcely be noticeable upon taking 
she skins down, but which after causes a reaction at the 
end of a few days, especially when the skins are piled or 
packed up, and then it is too late to remedy it. The calf- 
skins arrive, having lost their fine appearance, for the 
want of due care in the last operation. 

It is better to let the calf-skins rest in the wax a while 
for the following reasons : Although the skin be well 
rubbed and dry under the brush, jet the fatty particles 
of which the wax is composed quickly penetrate it ; but 
if it has been dressed too thin in finishing, the impression 
is momentary and gives the grain a marbled appearance. 
We must let it take its time in quiet, in summer eight 
days, and in winter from ten to twelve days are sufficient. 
After this pile them up in dozens, and take care to cover 
them up properly to protect them from the dust. 

A. workman who makes waxing his business, always 
prefers calf-skins whitened with the shaving-knife ; the 
flesh side gone over more lightly, is brushed better, the 
penetration of the dressing is more perfect and speedy ; 
it is easy to clean, which is not so with skins finished 
up with the instrument for the purpose. With this the 
flesh side is left open ; the wax penetrates them with 
difficulty, and it often happens that the workman, in 
order to get along faster, makes his wax thinner, and 
runs the risk of not penetrating them sufficiently. Calf- 
skins which have been whitened with the shaving-knife 
gain more in weight in waxing than those whitened with 
the knife for the purpose; but it must not be forgotten, in 
comparing the two, that the former lose in shaving as 
much as they gain in waxing, so that after waxing the 
difference between the two has disappeared. 

We give the preference to calf-skins whitened with 



556 CURRYING. 

the shaving-knifej and the English, who are celebrated 
for the fineness and finish of the flesh side, never use 
anything else. The American curriers, who have derived 
their principles from the English, likewise give their 
preference to calf-skins whitened with the shaving knife. 



CHAPTER CXX. 

GEAINED CALF-SKINS. 

The first operation consists in moistening the skins 
selected for this manufacture. This done, pare down 
the heads in order to equalize the thickness ; place them 
on the table, and scrape them with the stretching-iron. 

Next, beat them with the pestle in a tub of water, 
smooth them on both sides upon the marble, in order to 
reduce the natural grain of the leather ; then dry par- 
tially. Apply the blacking on the hair sides ; smooth 
the skins again, and oil them on both sides. Dry them, 
and deprive them of the excess of oil by means of a lye 
of potash. Smooth them upon the grain with the 
stretching-iron. 

In order to furrow the surface with the grain, place 
the leather upon the table, with the hair side up, and 
pommel first crosswise, then from tail to head, being 
careful that the lines which correspond in direction shall 
be perfectly parallel. Use for this purpose a pommel 
with 45 to 50 teeth to the inch. 

Apply another coating of black, and when absorbed 
brush over the surface oil and scouring train oil, in suffi- 
cient quantity for the requirement of the leather ; then 



GREASING TANNED HIDES. 557 

dry it. Pommel the hair side in the same manner as 
before. Pare the borders upon the horse with the round 
knife, and at last spread over it a light coating of pure 
and clear oil. 



CHAPTER CXXI. 

CALF-SKIN LEATHER FOR BELTS. 

Cut off the heads and extremities of the skins, soak 
them in a tub until sufficiently wet, shave them upon 
the horse with the head-knife until equally thick. Beat 
them in a trough with the pestle, dry them, and grease 
them slightly upon the flesh side with a mixture of equal 
parts of tallow and oil, and on the hair side with linseed 
oil alone. Then dry them and work them upon the 
flesh side with the stretching knife, and sleek upon the 
grain with the glass. Sometimes a grain is given as 
above described. 



CHAPTER CXXII. 

GREASING TANNED HIDES. 

Mr. George Huttelmaier, of Alleghany, Pennsylvania, 
has invented a new and useful improvement in the pro- 
cess of greasing tanned hides, and patented it in Septem- 
ber, 1863. 

In the process of greasing tanned leather, it is required 



558 



CURRYING. 



that the tallow should penetrate it thoroughly, and, in 
order to effect this, he finds it very desirable to expose 
the leather to a moist heat, sufficient to open the pore? 
of the skin and to keep the tallow melted during the 
whole process, and at the same time to apply friction to 
the leather so as to rub the grease well in. Where this 
operation is carried on by hand, as is usual, it is obviously 
impossible to secure all these conditions as the heat 
required is too great, and even if the tallow be melted 
and sufficiently heated when first applied, it soon becomes 
cool when exposed to the external air. 

His invention, then, consists in applying the tallow to 
the tanned hides in a suitable closed vessel, which is 
previously heated by steam, and which will retain suffi- 
cient heat during the continuation of the process and 
simultaneously applying to the leather a constant friction 
to rub in the melted grease. To effect this, he uses the 
following apparatus : — 

Fig. 145 is an end view or elevation of the apparatus. 



Fig. 145. 




GREASING TANNED HIDES. 



559 



Fig. 146 is a side view. 



Fi^. 146. 




Fig. 147 is a section through the centre of the appa- 
ratus, in the plane of its axis, showing the construction 
of the interior. 




560 



CURRYING. 



Fig. 148 is a transverse section of one-half of the 
apparatus at right angles to its axis. 

Fig. 148. 




In the several figures, like letters of reference desig- 
nate similar parts. 

The apparatus consists of a large cylindrical wooden 
vessel, which should not be less than ten feet in diameter 
and of any convenient length, although its dimensions 
may be varied to suit any desired capacity. This vessel 
may be conveniently made like a barrel, the circum- 
ference being constructed of wooden staves, g, g, about 
1 h inch in thickness ; these staves are bound together by 
strong iron bands or hoops ^, i, surrounding the vessel at 
suitable distances apart ; the hands or end pieces, u, of 
the vessel are also made of wood, and are supported by 
a circular iron plate b, h, in the centre of each end piece, 
to which are fastened arms cZ, d, which radiate from the 
centre of plate h, h ; the arms are fastened to the central 
arm plates by screws e, e, and the end pieces are like- 
wise bolted or otherwise fastened to the arms d, d ; in 



GREASING TANNED HIDES. 561 

one of the end pieces is a door /, through which the 
tallow and leather are inserted in the cylinder ; from the 
centre of each of the circular iron plates h, projects a 
journal h, on which the cylinder revolves in suitable 
bearings I, which are supported by the framework a, a, 
sustaining the entire cylinder. 

Around the outside of the cylinder at any convenient 
point is a band or hoop A, furnished with cog-teeth, 
which gear into a pinion g, to which motion is commu- 
nicated from the steam engine or other primary motion. 

Inside the cylinder, the staves comprising its periphery 
are studded with a number of pins p,^, projecting there- 
irom and pointing towards the centre of the cylinder. 
These pins should be about two inches in length, and 
may be fastened to circular ribs m, attached to the 
staves g, g. 

The apparatus thus described may be varied in size, 
shape, or construction, so that the designed effect is pro- 
duced. 

Before inserting the tallow and the tanned hides into 
the cylinder, it is previously heated by injecting steam 
for a sufficient length of time, to make the staves and 
ends of the cylinder so hot as to ba perceptibly felt from 
the outside, and so as to secure a temperature in the 
cylinder, after the steam is allowed to escape, of 
about 180°. 

The injection of steam is then discontinued, and any 
condensed water allowed to escape at the door /, or other 
aperture for that purpose. 

The tallow, previously melted by gentle heat, is then 
poured into the heated cylinder, and the tanned hides, 
in a half dry state, are inserted and the door securely 
closed. 

36 



562 CURRYING. 

The proper quantity of tallow will vary according to 
the quality and kind of leather to be greased, but one 
hundred pounds of calf-skins will require about 10 lbs. of 
tallow. The revolution of the cylinder is then com- 
menced, and continued for two or three hours more or 
less, according to the quality and quantity of the leather 
inserted therein, care being taken not to fill the cylinder 
so full of hides as to interfere with a constant and violent 
motion of the leather, which, being carried round by the 
pins j9, p, should be able to fall from the top of •the 
cylinder on to the points of the pins at the boftom. 

By the moist heat conta^ined in the cylinder, the pores 
of the leather are kept open, and the tallow is kept so 
hot as to enter it readily, while the continued rubbing 
of the hides on the pins causes their complete saturation 
with grease. 

Thus by means of the combined high heat and constant 
friction, a result is attained far superior to that which is 
accomplished by any degree of heat and rubbing which 
is attainable when the hides are greased by hand, or in 
vessels not so heated. 

This process produces a very durable solid and yet 
pliable and elastic leather, superior in these respects to 
that made in the ordinary way. Care should be taken 
that the hides are of a uniform degree of moisture, com- 
monly called half dry, before they are inserted into the 
cylinder ; if too dry in spots, they should be wetted in 
those places before they are put in, otherwise the greasing 
will not be uniform. The leather greased by this pro- 
cess is finished in the usual manner. 



SATURATION" OF LEATHER WITH GREASE. 563 



CHAPTER CXXIII. 

Saturation of Leather with Grease, 

In the saturation of leather with grease, a very 
faulty system is in some cases followed, from its being 
believed that leather must be dry in order to absorb the 
grease, and become thereby more enduring and flexible. 
Precisely the contrary of this is the fact. However 
incomprehensible it may appear at first glance, moist 
leather combines easier with oil or grease than dry. 
This seeming paradox is, however, easily explained ; dry 
leather is drawn closely together, its pores are closed; 
and, therefore, it absorbs ftitty bodies only slowly ; moist 
leather, on the contrary, is expanded and flexible, and 
its pores are open. If it is smeared over with oil or liquid 
grease, this penetrates the pores easily, entering even 
into the smallest as soon as the water disappears, and 
its evaporation is facilitated by the opening of the pores 
which have absorbed the oil. It is easy to convince 
one's self of this effect of oil upon moist leather. 

Take a small piece of wet leather, or a wet boot, place 
it in a warm place where it can dry slowly, and it will 
become quite hard and brittle ; but if you smear it with 
oil and grease, it will retain its pliability, and after being 
thoroughly dried, it will not have been in the least im- 
paired. Moist leather smeared with grease may, there- 
fore, be dried by heat without detriment. If dry leather 
be saturated with warm grease, the durability of the 
leather will be much impaired, because the heat contracts 
the fibres, and the oil easily acquires such a heat. The 



564 CURRYING. 

saturation of boot soles, as well as the rubbing in of 
sand or fine iron filings, is only practicable when the 
shoemaker turns the inner or flesh side of the leather 
outward. This possesses also another advantage. The 
flesh side has wider pores, and is less firm than the outer 
side. If the latter — the outer side — is made the outside 
of the sole, it will speedily give out, as soon as the hard 
external surface is worn away, for the soft inner side can 
offer no further resistance ; and, moreover, it does not 
absorb the grease owing to the smallness and rigidity of 
the external pores. If, on the contrary, the soft side is 
turned outward, then the side takes in a considerable 
quantity of wax, grease, and oil, and it will be more 
pliable and enduring; and even after this originally 
soft, but now enduring portion has been worn out, there 
still remains the hard part, the outward hide side being 
a guard sole, which can be worn to almost the thinness 
of paper without giving out. The most enduring soles 
of this description are made from the neck of the hide, 
having the fleshy side outward, and properly impreg- 
nated with wax and grease. The only fault that they 
have is this, that in walking upon grass, on account of 
their smoothness, you are apt to slip ; but soles saturated 
with grease are not only softer to the feet, but cooler, 
which is a great advantage in summer. 



CHAPTER CXXIV. 

CALF-SKINS CALLED ALUMED SKINS. 

These skins are chiefly employed by bookbinders. 
The process of making them has been described at length 
by De La Lande, from whose work we extract the follow- 
ing :— 



CALF-SKINS CALLED ALUMED SKINS. 565 

For the manufiicture of this leather select dry skins 
of stillborn calves or others of low price ; reject those 
injured by weevils or worms. When you open them, 
beat them strongly with a stick, and deposit them in a 
place not too warm or too damp. Work at a time thir- 
teen dozen of dry skins. Deposit them in an oval pit, dug 
out in the ground ; this pit is from eleven to thirteen feet 
long, by three and a half to four and one-third feet wide, 
and six and a half feet deep. Pass the water into this 
pit by an oval aperture, one and a half feet in height 
and narrow enough to prevent the skins escaping from 
it, and draw away by another similar opening. 

Leave the skins in the pit for two or three days in 
summer and six or eight in winter. Take them out, 
stack them, and next day scrape them upon the horse 
with a blunt knife. Deposit them again in the vat, leave 
them two days, scrape them as before, and if they are 
not sufficiently soft, expose them a third time in the pit 
for one day and scrape them. Place them in the lime 
pit, which is a hole about five feet deep, with a propor- 
tionate breadth and length. Into this pit throw from 
forty to fifty buckets of water and a cask full of lime, 
which is left to slack for twelve or fifteen hours. Stir 
the contents of the pit with a long pole, deposit in it the 
skins singly, and dip them with a stick. Leave in the 
lime pit for a day, take out, spread, and stack them ; 
pass them subsequently, in the same way, through new 
lime pits, gradually increasing the strength until the 
hair is ready to be removed. Wash them well in running 
water, depilate and deposit them again in a vat ^similar 
to the first described; let them soak one night, being 
kept in position by a long heavy pole placed longitu- 
dinally above them. This done, the skins are well 
fleshed upon the horse with a sharp knife until the flesh 



566 CURRYING. 

side can scarcely be distinguished from the grain. Thin 
down the necks until they become of equal thickness 
with the other parts of the skin. Cut off the ears, tails, 
and other extremities, and use them to make glue. 
Return the skins to the first pit, leave them over night 
in water, and work the hair side on the horse to expel 
the lime. After this, empty three or four bucketsful of 
dogs' or chickens' dung into a large vat and mix it 
thoroughly with a bucketful of water by stamping upon 
the mixture with the feet. Throw cold water in the 
vat until half full, and mix in some hot water. Throw 
the skins in, and stir for a few minutes with sticks, draw 
the liquor into a boiler and heat it, and the skins, after 
having been left for one hour are arranged in a corner 
of the vat, and kfept in place by two sticks crossed over 
each other. Pour the hot liquor in the empty part of the 
vat, a bucketful at a time, stirring all the time ; mix with 
the cold liquor so as to avoid injuring the skins by scald- 
ing. When the water is sufficiently hot, remove the sticks, 
and stir the skins around in the vat three or four times. 
Return the liquor to the boiler, and repeat the same 
operation, being careful not to add the hot water too 
rapidly to the contents of the vat and to try its tempera- 
ture frequently with the hand. Leave the skins in for 
half an hour. 

Collect the skins in a corner of the vat, and examine 
them ; stretch them in every direction, and when per- 
fectly pliable and soft they are ready to be taken out. 
At first, remove one or two dozen of those most advanced 
in preparation, deposit them in buckets ; then empty 
the vat of water as before, and turn the skins three or 
four times. A quarter of an hour after fill the boiler again, 
collect the skins together ; take out more of them, and 
so on until they are all removed. 



CALF-SKINS CALLED ALUMED SKINS. 567 

This part of the operation must be done very carefully, 
for if the skins are allowed to remain in the hot mixture 
after reaching the proper point, they are rapidly softened 
and destroyed. A repetition of the process described, 
continued for six or seven hours, is sometimes necessary 
for imparting the requisite qualities to the stronger skins. 
Experience alone can guide to determine the proper time 
for removing them from the vat. When this is done 
take out the skins from the vat ; stretch them and scrape 
them upon the beam, in order to soften, distend, and 
clean them ; and if any are found too firm, they are 
replaced in the vat while the rest are washed. Then, 
allow the contents of the vat to escape through the 
bung-hole. Wash it well, and fill it half with clear 
river water while you throw in a basketful of fresh tan. 
Wash the skins and stir them in this water with sticks, 
and leave in the vat till next day. Take them out; 
drain upon planks, and transfer them to the care of the 
sempstress. She then examines every skin, and closes 
any holes which may exist in them. The skins, except- 
ing the tail part, are then sewed with the flesh side 
outwards into the form of a bottle. For this purpose she 
uses a large needle, flat at the point, and with a double 
thick thread, stitches one part of the skin at a distance 
of one-fifth of an inch from the edge, and the other that 
of half an inch, turning over the latter upon the former 
in a hem, but not pressing it down tightly enough to 
prevent water from draining through, or to cause the 
production of dark spots and lines after tanning. A work- 
man places in each bag a quantity of tan proportioned to 
its size ; after which the sempstress sews up the tail part, 
closed by the hind legs, so as just to permit the introduc- 
tion of a copper socket for a wooden funnel. The bags 
are then brought near to a vat in which the tanning has 



568 CURRTING. 

just been completed. The sacks in this vat are removed to 
a rack in order to be unripped. The vat is left half full of 
the old liquor, and there is poured into it a quantity of hot 
fresh liquor, sufficient to make the contents lukewarm. 

' This fresh liquor is prepared by pouring the contents 
of the already tanned sacks into a vat provided with an 
upright door or partition at one end, through which the 
liquor which has drained from the tan passes, and col- 
lecting in the empty space is transferred to a boiler. 
The workman then takes a bag of skins, and empties 
into it, through the funnel, a small bucketful of water, 
and closes the mouth by tying it up with a small strip 
or thong which had been previously cut from the skin 
for the purpose, and left hanging from the tail; the 
bags having each been filled with the same quantity of 
water and then placed in the vat, and left for an hour, 
while another portion of liquor, prepared by percolating 
through tan, is being heated in the boiler. The work- 
man then places the bags upon a rack at one end of the 
vat into which the heated water has been poured, fills 
them again through the funnel from his little bucket, 
tying them as before, by which they are made to assume 
a pyramidal ^hape in the vats. Kepeat this operation 
a third time at the expiration of one hour, increasing 
the heat of the liquor as before. The liquor should be 
less heated for those skins which have been a long time 
in the lime-pits than for those which have been a shorter 
time, but the skill exhibited in making this distinction 
can only be acquired by long experience. Next day 
perform a similar operation in a third vat, while the 
bags deposited the day before are left to soak in the vat. 
The third day take out the skins of the first vat, and 
leave to drain upon a rack placed over the vat. Throw 
them upon the rack in the vat, upon which they are 



jahkel's process. ' 569 

unripped and emptied of their tan. Fold them with the 
flesh side within, and wash them in running water; 
place them upon a trestle to drain ; open them at the 
hindquarters, and hang up in a shed, with the heads 
down, on nails placed some distance apart. 

When dry, pile them up, and leave them until ready- 
to be sent to market. Then moisten them, in summer, 
by exposure to the dew of night air ; tread them out in 
order to render them supple and to efface the marks of 
the sewing; assort them, according to size, into packs of 
six each, which are tied together by the heads with pack 
threa^d. 

Hog-skins used by bookbinders for Bibles and church 
books, are prepared in the same manner as calf-skins, 
but they differ from them in being exceedingly thick 
and strong. 

Tanned sheep-skins, used by bookbinders, are not 
alumed as calf-skins, but are only limed and tanned. 
Some of these are sewed up and tanned similarly to the 
calf-skins, while others are tanned by stratifying them 
with bark. 



CHAPTER CXXV. 

F. JAHKEL'S PKOCESS FOE MANUFACTURING LEATHER 
FOR HARNESS-MAKERS. 

The fine brown leather made in England for saddlers' 
uses is very highly esteemed, and, notwithstanding its 
high price, is much sought after, being superior to any 
other in suppleness, density, and color. 

Its excellence is not attributable to any novelty in 
the process employed in its manufacture, or to the use 



570 » CURRYING. 

of complicated machinery, but solely to the care with 
which the materials are selected, and to the skilful and 
accurate manipulation of the workman. The finest 
skins used for this leather come from cattle raised in 
Wiltshire and Somersetshire, the climate of which coun- 
ties seems to be the best adapted to secure the develop- 
ment of tissue in these* animals, and particularly of the 
firm, elastic, and resisting integuments, which are so 
necessary for the production of grain leather. 

Skins of cows or of young bulls are preferred. They 
are usually tanned in the neighborhood of Bristol, and 
sent to London, where the best are selected by the man- 
ufacturers. 

The processes of tanning are similar to those elsewhere 
employed, and comprehend, besides liming and depilating, 
the use of grainier s of chickens' or pigeons' dung, dipping 
immersion in tan baths of difierent strengths, and two 
separate tannings in pits with fresh barks of the finest 
quality. The currying which this leather undergoes 
serves to remove its original dryness, stiffness, and depth 
of color, and to render it supple, elastic, and impervious 
to moisture, without diminishing the solidity and density 
of structure given to it by the tanning. 
• At first, cut the leather in half along the length of the 
skin, and repeatedly soak it ; beat it, and wash it in cold 
water to dissolve and remove the gallic acid and ex- 
tractive matter, which, if allowed to remain, might by 
oxidation deepen the color, and interfere with the pro- 
per absorption of the substances which are afterwards 
applied. After all foreign bodies have been removed by 
these means, the skins, although saturated with tannin, 
are yet in a condition which enables them to absorb 
sumach; and accordingly they are deposited in a bath con- 
taining one-quarter of their weight of powdered suraach. 



CURRYING OF GOAT-SKINS. 571 

Take the leather out, and dip it again in a new position 
two or three times every day while in this bath, stirring 
every time the powder which has settled to the bottom. 
At the end of the second day add a quantity of sumach 
equal to that already used. Take the skins at the end 
of three days ; they are found to be not only improved 
in color, but more soft and pliable than before the treat- 
ment. To more completely develop the lustre-like yel- 
low color of these skins, they are washed in water to 
remove the sumach, and then passed repeatedly through 
a very weak bath of sulphuric acid, being quickly taken 
out after each immersion, and immediately rinsed in 
pure water to take up the acid, which, if allowed to 
remain, will destroy the leather. 

Dry the leather ; then oil it upon the flesh side with 
pure cod-liver oil, and when thoroughly penetrated by 
this, oil it with a mixture of best whale oil with half its 
weight of tallow; in the meantime, scraping as usual upon 
the grain with the fleshing-knife. Then pare it, sleek 
and beat it out flat. All these operations are performed 
with the hand, without the help of any machinery. The 
excellence of the products depends entirely upon the 
skill and attention of the workman. 



CHAPTER CXXVI. 

CURRYING OF GOAT-SKINS. 

The preparation of these skins, on account of their 
great thinness, requires as much care and labor as calf- 
skins. The currier receives them dried, after having been 
oiled. At first he softens them by soaking for 24 hours 
in a vat full of water; he treads them out under the 



572 CURRYING. 

feet three at a time, and scrapes them upon the flesh side 
with a blunt knife. When nearly dry, he oils them 
with a mixture of train and scouring oil. A dozen of 
skins weighing from 18 to 20 lbs. requires from 6 to 8 
lbs. of oil. The oiling being completed, he again treads 
tham out, scrapes clean and pommels with instruments 
smaller than those used for calf-skin. To free the surface of 
the excess of oil, and to soften and brighten them, he dis- 
solves 4 ounces of potash in two bucketsful of water, and 
passes lightly the solution over the grain side, the sapo- 
naceous compound which it forms is wiped off. The 
above quantity of potash is sufficient for six dozen of 
skins. 

After this operation, grain the leather with the pom- 
mel, and rub it with a bunch of straw to soften the grain. 
Wipe it well with a woollen rag, and black it with the 
following mixture: one ounce, powdered nutgalls, one 
pound copperas, and a handful of Brazil wood ; the whole 
is boiled some time in a little porter and then stirred in 
a bucketful of the same liquid. Black six skins at a time, 
and pile them upon each other on the table or floor. 
Then turn the pile, so that those which have been black- 
ened first become uppermost, and wipe thoroughly each 
one with a woollen Tag, and stretch them to dry. When 
the skins are partially dried, black them a second time 
with a hard brush, distribute the color over the surface 
rapidly and uniformly, then wipe them with a roller 
made of blanket stuff", and dry them in the air. Pommel 
them now across the grain, wipe, moisten with sour beer 
applied upon a piece of listing, and rub with a bunch of 
straw to reduce the grain. 

This operation done, trim the borders upon the horse, 
pare the skins with the round knife, pommel and brighten 
with barberry juice. This last operation must be done 



CURRYING OF GOAT-SKINS. 573 

carefully, and is performed by passing the listing, dipped 
in the polish, rapidly and lightly over the surface from 
head to tail and across, continuing to rub while the rag 
remains moist and until a polish is given. Then apply 
the roller equally and forcibly to the whole surface from 
head to tail, pommel the skin lengthwise and across, and 
dress upon the grain with pure linseed oil. 

Formerly it was the fashion to form a diamond grain 
surface upon goat-skins, but now they are grained in 
straight parallel ridges, formed by pommeling from head 
to tail alone. 

We will now describe another mode of preparing goat- 
skins indicated by M. Dessables : — 

Sprinkle two skins at a time, upon the hair side, with 
water from a brush, and place them upon each other with 
their hair sides in contact, and fold them up into a cap- 
like form, beat them with the feet or the mace. 

Pommel them from head to tail and crosswise, slightly 
moistening them at the same time with water. After you 
have prepared a dozen or more skins in this way, place 
them in a tub with a sufficient quantity of water to 
cover them, beat them with the rammer, stretch out 
and smooth them upon the marble with a stretching 
iron, and dry partially. Then wash the hair side over 
with a weak solution of potash, scrape the skins upon 
the flesh with the stretcher, rub over with a bunch of 
straw, stretch again and wipe with a piece of woollen 
cloth before blacking. The color is prepared as in the 
other process. Spread this blacking lightly with a brush 
over the hair sides, and dry. 

Sometimes instead of pure water a solution of potash 
is used to moisten the skins. 

When dry, apply to the skins a second coating of color 
with a hard brush made of hog's bristles, pass it rapidly 



574 CURRYING. 

over the surface, and press upon them with considerable 
force. Then wipe the hair side with a woollen cloth 
made into the form of a roller, and pommel lengthwise. 
Pare the edges with the head-knife, scrape the leather, 
and wipe it again, and at last pommel so as to produce, 
quadrilateral figures. Polish the blackened surfaces by 
rubbing them with a piece of cloth dipped in barberry 
juice, smooth with the roller, and oil upon the hair side 
with linseed oil ; this completes the operation. 



PROCESS OF MANUFACTURING RUSSIA LEATHER. 575 



SECTION IX. 

RUSSIA LEATHER. 

The Russians have manufactured for a long time a 
variety of fancy red leather called by them Juncten. 
This leather has an agreeable and characteristic odor, 
does not mould even in damp places, and is not attacked 
by insects. This process was described by Pallas and 
by Fischertroem, and a factory was established in France 
at St. Germain more than 70 years ago, under the 
auspices of M. Feybert, but did not prove successful. 

The process we are going to describe is taken from 
the prize work on the subject by Grouvelle and Duval- 
Duval, and of Mr. Payen,* but all these methods are de- 
fective, and the Russian process is not yet entirely known. 



CHAPTER CXXYII. 

PEOCESS OF MANUFACTURING RUSSIA LEATHER. 

Calf-skins and goat-skins dyed generally of a red color, 
cylindered and impregnated with a purified empyreu- 
matic oil obtained from the birch tree, constitute Russia 
leather. For this object select the whitest and most 
perfect skins. Deprive them of hair by steeping them 
in a mixture of ash lye and quicklime made too weak 

* Dictionnaire technologique. 



576 RUSSIA LEATHER. 

to act on the fibres. Rinse; full them a longer or shorter 
time, according to their nature ; wash in hot water, and 
ferment in a proper steep. Leave eight days ; take out; 
full again ; steep a second time if necessary to open their 
pores ; clean with the flesh knife on both sides. 

For 200 skins make a paste with 38 lbs. of rye flour 
fermented with leaven ; work the dough with a sufficient 
quantity of water to form a bath for the skins; soak 
them forty-eight hotirs ; transfer them to small pits ; let 
them remain fifteen days ; wash them well. This pre- 
liminary operation serves to prepare the skins for their 
uniform and complete combination with tarmin and ex- 
tractive matter. 

Then make a decoction of willow bark, and when the 
temperature is sufficiently lowered to prevent it from 
injuring the fibres, immerse the skins in it; handle and 
work them for half an hour. Repeat this operation 
twice daily during a week, after which prepare a fresh 
decoction, and submit the skins to the same treatment 
for another week. Then dry them in the air, and they 
are ready to be dyed and dressed with the oil. 

Dessables has given another method of preparing the 
skins for the chief operation. 

Select the whitest and most perfect skins ; soak them 
in water ; scrape them upon the beam ; full them ; work 
with the pommel, and then oil them upon the flesh side 
with pure fish oil, and upon the hair side with train oil 
scouring. Dry them ; pommel them again ; wash over 
the hair side with a solution of alum, and then press 
under the cylinder. This cylinder, by which the dia- 
mond-shaped grain is given to Russia leather, is made 
of steel, 12 i^ inches long, and 3 inches in diameter, and 
is covered with a number of closed' parallel threads or 
grooves like those of a screw, but cut perpendicular to 



PROCESS OF MANUFACTURING RUSSIA LEATHER. 577 

its axis and not spirally. This cylinder is filled with 
stone weighing from 300 to 400 lbs. It is moved in 
two directions upon a wooden bench, by means of a cord 
passing round a wooden roller with a handle ; this cord 
also passes over two cylinders attached to the floor and 
a fourth one upon the end of the bench. The cylinder 
having the handle upon its axle is divided into two dif- 
ferent parts, over which the two extremities of the cord 
pass in different directions, so that two opposite move- 
ments can be given to the cylinder by one handle. The 
cylinder is sustained and directed by iron bars placed 
along the bench upon which it rolls. The skin which 
is to be grained is placed below it lengthwise upon the 
bench, and longitudinal grooves are impressed upon its 
surface by the track of the cylinder. The skin is then 
removed, and again placed upon the bench, either cross- 
wise or at an angle, according as it is intended to give 
it a square or a diamond-shaped grain. 

When the skins are properly grained, apply to them 
a second coat of alum water, and when nearly dry spread 
over the hair side the Russian oil, and give the black or 
red color. Then expose the skin repeatedly for a short 
time to the direct rays of a hot sun, until the color has 
sufficiently penetrated its substance; then full; pommel; 
sleek with the round knife upon the beam ; and at last 
rub well upon the hair side with a hard brush. 

The principal characteristic of the preparation of Rus- 
sia leather is its impregnation with birch-bark oil, the 
fabrication of which is still in a measure kept secret. 
In order that the oil should penetrate the leather pro- 
perly the latter must not be either^too moist or too dry, 
but should contain just sufficient water to enable the oil 
to be spread equally over the surface, and to be absorbed 
in proportion as the moisture gradually evaporates. The 
37 



578 RUSSIA LEATHER. 

leather thus prepared retains the characteristic odor for 
a long time. You must be careful not to apply too much 
of the oil, for fear of its passing through and staining 
the grain side. To fully impregnate a large cow-skin, 
from twelve to sixteen ounces are sufficient. In case 
the leather is not dyed, or of morocco to which you 
wish to impart the odor, only a very small portion should 
be applied to the flesh side. 

The composition of the red color of Russian leather 
has not been accurately ascertained. It usually contains 
Brazil wood, alum, and some other substances. It is 
not very durable, and does not resist the action of boiling 
water or of potash, but remains unaltered in the air. 
Other dyes of better quality are sometimes used which 
enhance the price of the leather. Black Russia leather 
is prepared in the same way as the other, and is stained 
by the repeated action of acetate of iron. 



CHAPTER CXXVIII. 

DISTILLATION OF THE EMPYREUMATIC OIL OF BIRCH- 
TREE BARK FOR RUSSIA LEATHER. 

Much attention has been bestowed upon the manufac- 
ture of the empyreumatic oil of birch bark, and quite a 
number of different modes of preparing it have been de- 
scribed, we shall give the most important. 

Fischer stroerri s Process. 

Separate very carefully the whitish membranous epi- 
dermis of the birch from all woody matter. Introduce 
it into an iron boiler, which, when full, is covered with 
a vaulted iron lid, from the centre of which issues an 



DISTILLATION OF THE EMPTREUMATIC OIL. 579 

iron pipe. Place over this boiler another one, into which 
this tube enters without touching its bottom. Bolt the 
edges together and lute tightly. Invert them so that the 
one containing the bark is uppermost. Sink in the earth 
the lower half of this apparatus, cover over the surface 
of the upper boiler wdth a lute composed of clay and 
sand, then surround it with a wood fire, and expose to 
a red heat until the completion of the distillation. As 
soon as the boilers are cooled, disconnect them. In the 
upper one you find a light charcoal powder, and in the 
under one, used as a receiver, is a brown oil, odoriferous, 
empyreumatic, mixed with tar and pyroligneous acid. 
Separate the oil from the other substances and keep it in 
a close vessel. 

Another process. — Introduce the dark birch bark into a 
large earthen pot, having a hole in the bottom. When 
the pit is full, set the bark on fire -, over that pot invert 
another similar pot with a hole for the escape of smoke, 
and this latter is placed upon a bucket, into which the 
tar and oily matters drop as they are formed. 

If the preparation is made in the spring, some manu- 
facturers mix the young branches of birch covered with 
buds with the bark. This arrangement facilitates the 
separation of the oil, which, when thus prepared, is of 
a lighter color, from the smaller quantity of soot it con- 
tains. 

Grouvelle and Duvdl-DuvaV s Process. 

They take the white epidermis of the birch bark, well 
separated from all ligneous matters, and introduce it 
into a copper still, similar to those used to distil wood 
to manufacture pyroligneous acid. They adapt to it a 
receiver immersed in water, in which the gaseous pro- 
ducts are condensed. As in the fabrication of pyrolig- 



580 



RUSSIA LEATHER. 



neous acids, the resulting products are pyroligneous acid, 
tar in larger quantity, and the empyreumatic oil more 
colored and less abundant. This oil is obtained nearly 
colorless by a rectification, but this rectification is not 
useful except in case the oil has to be used for skins very 
lightly colored. 

Payefis Process. 

By repeating the distillation per descensum of the epi- 
dermis of the birch bark, Mr. Payen has ascertained that 
with a very simple apparatus, it is possible to obtain an 
oil less colored and in the proportion of one-fifth more, 
at a temperature less elevated. 

His apparatus, represented below, is thus formed :— 




A hole is made in the bottom of an earthen furnace A, 
large enough to receive the neck of a matrass M. The 
furnace is supported by two bricks placed upon the plank, 
which is also perforated so as to admit of the passage of 
the neck of the matrass, and which rests upon the trestles 



DISTILLATION OF THE EMPYREUMATIC OIL. 581 

C, C. The matrass is filled to its utmost capacity with the 
epidermis of birch bark, it is inverted and passed through 
the furnace and the board. Then the neck is luted and 
placed in the position seen in the figure, being supported 
by sand thrown into the bottom of the furnace as high as 
F, F ; and in order to expose the matrass to a uniform 
heat, it is protected by inverting over it an earthen 
hemispherical vessel or crucible. Around this, burning 
coals are placed, and the fire is kept up through two 
lateral openings D, D, the dome T, K, L, being placed 
upon the furnace top. Condensed water first trickles 
from the mouth of the matrass into a vessel placed be- 
neath, and this is succeeded by drops, and then by a 
constant stream of an amber colored oil. After a time 
this ceases, and it is necessary to apply heat lower down 
to the neck of the matr.ass, so as to cause the discharge 
of the last portions of all and tarry matters which have 
condensed in it. 

The products obtained by the distillation of 100 parts 
are as follows : — 

A brown oily matter, light fluid empyreuraatic, solu- 
ble in ether tO.OO 

Thick dark brown tar containing a little oil . • 5.00 
Water acidulated with pyroligneous acid . . 10.00 
Light spongy charcoal . . . . . .12.50 

Gases 2.50 



100.00 



This oil may be readily obtained by distilling the 
bark in iron cylinders placed horizontally in a furnace 
similarly to gas retorts. 



582 RUSSIA LEATHER. 



CHAPTER CXXIX. 

NATUEE OF THE ODORIFEROUS SUBSTANCE OF THE 
BIROH-TREE BARK. 

Messrs. Payen and Chevalier have examined the 
odoriferous substance of the epidermis of the birch-tree. 
This epidermis contains from 0.2 to 0.3 of an imme- 
diate peculiar principle, white, pulverulent, soltible in 
alcohol, volatile. Thrown on incandescent charcoal it 
exhales abundant vapors, whitish, with an aromatic odor, 
sweeter than that of Russia leather. It is to this princi- 
ple, called Betuline by Mr. Chevreul, who discovered it 
first, that are due the characters proper to Russia leather. 
This principle can be assimilated to an insipid, odorless 
and colorless resin. By alteration it acquires a very 
fully developed odor. It is probable that by the distilla- 
tion per descensum a greater portion of betuline is carried 
away without alteration and in the fluid part. It is 
possible that in this state, it contributes more effica- 
ciously to the preservation of objects which are impreg- 
nated by it, a property which, as every one knows, is 
common, 1st, to resinous bodies not to be penetrated by 
dampness; 2d, to many volatile oils and odoriferous sub- 
stances, to preserve vegetable and animal substances sub- 
ject to spontaneous alteration. 



PREPARATION OF RUSSIA LEATHER. 583 



CHAPTER CXXX. 

PEEPAEATION OF BUSSIA LEATHER. 

Macerate calf-skins in a weak alkaline liquor, work 
them on the beam and wash them in water, dip them in 
a mixture of water and oat meal, and keep them in 
till a light fermentation is established. Birch-tree bark 
is preferable to oak bark. Stir all the time. The tanned 
skins are rendered supple by means of the oil ; they are 
then rubbed several times with the tar of birch-tree bark ; 
they owe their agreeable odor to this substance. Russia 
leather retains that odor for several years. 

This leather is blackened by rubbing it after tanning 
with pyrolignite of iron. In Astracan they prepare a very 
fine leather with elk or goat-skins. The operation is 
similar to that operated on sheep-skins. The leather is 
left for three days in a bath of fermented bran. Spread 
each skin in a bucketful of water containing a certain 
proportion of honey ; it is passed afterwards in a sour 
bath and then dried. This leather is dyed red by im- 
mersing it in a bath of cochineal containing an alkaline 
plant. It is then passed in a solution of alum and 
tanned. The red can be made brighter and more solid 
by using nutgalls instead of sumach. The yellow is ob- 
tained with the wild chamomile. 



584 RUSSIA LEATHER. 



CHAPTER CXXXI. 

COLORING OF RED RUSSIA LEATHER. 

Mr. Jno. Wagmijster, a tanner of Paggstall, has suc- 
cessfully imitated Russia leather by employing the red 
dyed cow-leather. He operates as follows : As a basis, 
take 5 ounces of nitric acid and heat it in a glazed vessel 
in a chimney flue, but not over an open fire, until it 
begins to smoke, that is, until a red fetid vapor rises ; 
which great care should be taken not to inhale. Then 
pour it over one pound of salt of tin and stir it with a 
long wooden stick. It is preferable to mix the salt of 
tin and the warm acid in the open air, or in a strong 
draught, so as not to be too much exposed to the danger 
of inhaling the vapor. The stirring with the skin should 
be carefully continued as long as the red vapor rises ; 
but as soon as white vapors commence to ascend, one- 
quarter of a pound of hydrochloric acid should be poured 
into the mass, stirring it briskly all the while. After a 
few minutes pour the liquid into the bottle and keep 
it for use. In filling the bottles care should be taken 
not to have the liquid too hot, or a bottle may easily 
burst and hurt the operator. 

The liquor until used should be kept in a place where 
the temperature is moderate, and in using it, from twelve 
to fifteen times its volume of clean water should be added 
to dilute it. 

After being thoroughly tanned and well washed, hides 
may be grained with this, that is to say, this corrosive 
substance may be well rubbed in by means of a brush. 
For the dye take 1 lb. Brazil wood, and boil it an hour 



COLORING OF RED RUSSIA LEATHER. 5S5 

in six quarts of clean river water. Then the limpid color- 
ing liquor must be strained off and three-quarters of an 
ounce of cream tartar dissolved in it. The coloring liquid 
with the tartar should be well boiled together for an hour. 
It is advisable to boil the coloring liquid separately several 
days before the tartar is added, as its strength will be 
increased thereby. 

As in black dyeing the hides should be smeared only 
on the flesh side, then fulled and wiped off with woollen 
rags, so that the half-moist condition may leave the 
grain open. After the hide is thoroughly dry, it should 
be crimped and well rubbed two or three times with the 
above-mentioned corrosive liquid, and then spread over 
also two or three times with the warm dyeing liquor ; if 
cold, warm it. In the preparatory operation as well as 
in the stirring, brushes should be used. The brush 
should not be dipped in the liquor, but the liquor poured 
upon the hide and the brush work begun at once in order 
to spread the stuff uniformly, and that the stained hide 
may show an even tone of color in all parts. The dye 
must be applied immediately after the first rubbing, 
because it is then moist and the color takes better and 
no small spots are left. Therefore it is better that two 
men should be used in this operation, each of whom 
dyes half a hide, both working together, thus the dyeing 
of one side and the staining of the other side will go on 
together. Should the color not take uniformly, the 
light spots must be gone over again with the dye. 

This red dye is very lasting, and endures as long as 
the hide itself, so that hides treated with this preparation 
may be kept on hand in the storehouse for further dress- 
ing. Hides that have been coated and long kept on 
hand dye badly; such should be soaked in luke-warm 
water, and then treated like fresh-tanned hides. 



586 RUSSIA LEATHER. 

As a last process, the stained leather should be moist- 
ened on the flesh side with tan liquor, sleeked, dried, and 
then grained and crimped j a handsome appearance may 
be given to that leather, by going over the colored side 
with lime water by means of a sponge ; the color receives 
a fine gloss and a peculiar fiery tint ; but the lime water 
should not be too strong. 



CHAPTER CXXXII. 

EXTRACT FROM A MEMOIR ON THE PROCESS OF TANNING 
SKINS IN RUSSIA BY THE COUNT OF KARTSOFF* 

The principal Russian manufactories are situated in the 
government of Misnie, Novogorod, Orlow, Moscow, Perm, 
Courks, and Wladimir. The city of Cazan possesses a 
very extensive establishment, but as it belongs to the 
government the products manufactured there are re- 
served for use of the navy. As for goat and sheep-skins 
proper for the fabrication of morocco, Cazan exclusively 
manufactures them. 

The Tartars are the principal workmen in these 
shops. Their process of preparing goat-skins differs 
from the other in this : that they use sour mares' milk, 
into which they pass the skins after the raising. It is 
this preparation which gives to the morocco the supple- 
ness which distinguishes it, and renders it proper for the 
diflerent uses to which it is intended. 

When the skins are dried, soak them in water to soften 
them • the degree of dryness and the temperature deter- 

* Bulletin de la Societe d'encouragement de I'iadustrie nationale, 
vol. xii. page 211. 



PROCESS OF TANNING SKINS IN RUSSIA. 587 

) 

mine the time of this operation. In summer they are 
left in water about five or six days, and in winter from 
ten to twelve days. 

The skins are washed to free them from the blood and 
impurities adhering to the surface ; for this pui*pose 
spread them and raise them as follows : — 

Throw the skins in water, to which some hydrate of 
lime has been previously added, and let them stay in the 
vats a longer or shorter time according to the strength 
of the milk of lime. Begin at first to put 160 lbs. of 
lime in each vat, and when the liquor weakens introduce 
a new quantity of lime. The vats are built of pine 
wood; they are 8 feet in diameter, and 6i feet in height. 
They are hooped with iron, and are sunk a few inches 
below the floor of the shop, so as to enable them to be 
covered with planks. 

For heavy leathers another method is followed : They 
are carried in an oven, and are spread one on the other, 
covering them with earth to prevent fermentation. A 
sour bath prepared with rye bran is sometimes used, 
principally for thin skins. 

The skins are inspected several times a day, to ascer- 
tain when the hair begins to loosen. Take it ofi* then 
with the epidermis, by working the skins on the horse 
with a two-handled knife ; then equalize the inside sur- 
face with a knife. 

To destroy the lime which has penetrated the skins, 
wash them several times. For this purpose a man in- 
troduces them one after the other into a vat, and beats 
them with the feet in turning them ; he soaks them with 
warm water till this water is clear; then he washes 
them, and lets them soak one or two days in running 
water. 

To this operation follows the tanning; but to have 



588 RUSSIA LEATHER. 

the tannin penetrate the skins, their pores are opened 
by swelling them ; for this purpose they are dipped in 
an acid liquor prepared with flour. For a vat of the 
size described above, they use sometimes 1000 lbs. of 
rye 'flour and from 4 to 6 lbs. of salt dissolved in 
warm water; sometimes 2000 lbs. of oatmeal, 6 lbs. of 
salt, and a little yeast. In some places they use spent 
tan. When the acid fermentation is established, put 
the skins in, and- leave them about forty-eight hours. 
Sixteen pounds of flour are used for a skin of an ordinary 
size. 

The skins thus disposed are exposed to the action of 
a weak infusion of oak bark or willow. Then they are 
spread on a wooden grate above the bark. They are 
piled up, and covered with bark, coarsely ground ; and, 
as you raise the pile, force the grate down the pit 
until it reaches the bottom, which is covered with a bed 
of the same bark. The pit being full, water the skins 
with spent liquor. They are covered with planks loaded 
with stones. Leave the whole from fifteen to eighteen 
days ; raise the skins, and change the bark. Eepeat this 
operation three and even six times according to the 
nature of the leather. 

When tanned, the leather acquires a certain stiflhess, 
which is corrected by dipping it from twenty-four to 
thirty-eight hours in a liquor composed of 120 lbs. of ■ 
oatmeal and 8 lbs. of salt, both mixed with water, so as 
to form a thin paste. This quantity is sufficient for 150 
skins of ordinary size ; wash them, and leave them to 
drain, and they are ready to receive the oiling. Fish 
oil and tar from birch-tree bark are the substances used 
for this operation, which is practised in the following 
manner : — 

The leather, being damp, is placed wrong side upon 



PROCESS OF TANNING SKINS IN RUSSIA. 589 

a table. The operator, having dipped his hand into the 
mixture, passes it over the skin by spreading it as 
equally as possible. 

The perfection of this operation depends upon the 
ability of the workmen. The proportions of oil and tar 
vary according to the size, nature, and quality of the 
leather. Generally one-third of tan and two-thirds of 
oil are used. Sometimes two-thirds of tan and a second 
coating are applied on the outside surface to render it less 
permeable to water. In some shops, where they desire 
to keep the skins as white as possible, they use pure oil, 
to which is added a little beef tallow, half a pound being 
sufficient for an ordinary skin. 

This operation completed, the skins are spread on 
ropes under a well aerated shade, where they remain 
until perfectly dry. In winter they are exposed to the 
frost which renders them white. 

The Baskirs and Kirguises used to prepare the skins 
with smoke, which takes the place of tannin. 

They begin by strongly stretching the skins when 
green, and taking off the hair with a sickle. The skins 
dried by the sun are kept in till the following spring. 

At that time a pit is dug, the size being according to 
the quantity of skins to contain ; poles are suspended 
on the top, their ends reposing on the edges of the pit. 
Then at about five feet they make a round hole which 
communicates by a little trench with the bottom of the 
pit. In this hole the combustible is placed ; this com- 
bustible is generally rotten wood, as the one giving the 
most smoke. 

This done, the fire is lit by shutting the aperture : the 
smoke passing by the trench penetrates inside the pit 
and spreads over the skins. After fifteen or twenty-one 
days of smoking, the skins are impregnated with the 



590 RUSSIA LEATHER. 

volatile products of the combustion, and acquire some 
of the properties essential to the tanning. They are 
more water proofs than European leathers.* 

The currying is done in Russia as anywhere else, only 
the leather is streaked with a long fluted copper plate 
about from 4 to 6 inches long and 3 inches wide, on 
which they bear the hand, which grains the surface. 

The process of preparing the tar is as follows : Take 
large earthen pots, the bottoms of which are pierced with 
a hole, which are filled with birch-tree bark well packed. 
They are placed on pails used as receivers. After light- 
ing the bark, they are covered with other similar vessels 
pierced with a hole by which the smoke escapes. The 
oil runs by degrees through the aperture of the lower 
vessel and falls into the pail which supports it. 

This operation is done in the spring, and they mix 
with the bark some branches covered with buds. That 
mixture facilitates the running of the oil, which is less 
colored than by the other process, the reason being that 
they dissolve less soot. This is why fresh bark is pre- 
ferred to that which is dry. As Russia prepares more 
oil than necessary for its consumption, a large quantity 
is exported. 



CHAPTER CXXXIII. 

EED LBATHEE. 

In former times this kind of leather was very largely 
manufactured, but is replaced now by Morocco sheep- 
leather; however, some is still manufactured, of a finer 
but of a less permanent color than Russia leather, and 

* Bulletin de la Soci^t6 d'encouragement, vol, xii. page 211. 



RED LEATHER. 591 

without its odor. These skins, used by harness, coach, 
and trunk-makers, weigh on an average from 10 to 12 lbs. 

To prepare red leather choose fine clean skins with a 
uniform smooth surface. They must not have been tal- 
lowed, but only softened with a little clear oil, which is 
passed lightly over the surface. Dip, pare, and wet them in 
water, give them a coating of clear oil on the hair side, 
and train-oil scouring on the flesh side. The proportions to 
use are half a pound of each. The skins are then dried. 
Press on the hair side with a brush, a solution of alum 
in water, which acts as a mordant to fix the color on the 
skin. The skins are then beaten to soften them, exposed 
to the air, and, when dried, they are rubbed with a cork. 
In that state they are dried. The color is prepared as 
follows : — 

In a clean barrel put from 8 to 10 lbs. of quicklime, 
with as much water, and let it stand for two days. The 
third day decant the water without stirring the lime 
deposited in the bottom. Put this water into a copper 
kettle. To prepare two pailfuls of red, take 8 lbs. of 
Brazil wood, and boil strongly with the lime water; as 
the water evaporates, add some more so as to have two 
pailfuls at the end of the ebullition. Put this liquid back 
on to the fire, and boil it until reduced to one-half; keep 
that solution in a separate vessel. Fill the kettle with 
lime water, reduce to half. Mix the two liquors in the * 
kettle, and add to this composition half an ounce of pow- 
dered cochineal, boil a few minutes and take off from the 
fire. While the liquid is yet boiling add a piece of lime 
the size of an egg, and let it cool. This dye is sufficient 
for eighteen to twenty skins. When the dye is ready, 
give to the skins a first coating, expose to the air, give 
a second coating, and leave it to dry completely. The 
skins are then pounded, and they receive a third coating 



592 RUSSIA LEATHER. 

to which a white of egg has been added. Expose to the 
air and sleek on the hair side. They are finally rubbed 
over in the usual way. with barberry juice, dried, and 
strongly sleeked. 

Dessables has given another process to dye the skins. 
He makes a solution of alum by dissolving in a kettle 1 
lb. of alum in li pint of water. When the solution is 
made he pours it into an earthen jar and adds to it 3 qts. 
of ordinary water. This solution is sufficient to mordant 
three dozen calf-skins. Afterwards take 3 lbs. of Brazil 
wood with a piece of lime the size of an egg. Boil the 
whole in 15 qts. of water for five or six hours. 

The skin being in the same state as for the black, it is 
well rubbed with a piece of wool dipped into the alum 
solution, then well dried and rubbed with the Brazil. 
Dry again, and rub with a piece of wool, apply another 
coating of Brazil, dry, and repeat the operation a third 
time. 



CHAPTER CXXXIV. 

SHAGEEEN AND PARCHMENT. 

Shagreen. 

The best quality of shagreen is manufactured almost 
entirely in A^tracan and other parts of Asiatic Russia ; 
gray and colored shagreens are imported from Constanti- 
nople and Tunis ; an inferior article is also manufactured 
in Poland. True shagreen is not real leather, but a skin 
prepared by drying, and without the chemical action of 
any tanning material. The following process is that 
which is said to be followed in Astracan. The raw 
materials employed are the skins of horses, asses, camels, 



SHAGREEN. 693 

and only the small strip from the cropper along the 
chine to the»-neck can be employed. This is cut ojQf just 
above the tail in a semicircular form, about 34 inches 
upon the cropper and 28 along the back. Soak these 
strips in water until the hair is ready to come off, then 
separate it by scraping. Afterwards dress the pieces 
with the fleshing knife until all extraneous matters are 
removed, and they have been reduced to the thinness 
of a hog's bladder. Stretch them tightly across frames, 
and occasionally dampen them to prevent them from 
shrinking unequally ; after which, lay them on the floor 
with the flesh sides undermost, and the grain sides are 
then thickly strewed over with the smooth hard seeds 
of the alabuta or goose foot {chenopodium album). In 
some places, instead of this mustard seed is used. Then 
lay a felt over the whole, and force the seeds deeply into 
the soft moist skins by treading upon them or by the 
action of a press. 

This operation gives to the hair side of the shagreen its 
characteristic granular appearance. Then dry slowly 
in the shade, the frames with the seeds sticking in the 
skins, until the skins are ready to drop off upon shaking. 
The skins are thus converted into hard horny membranes, 
with the surfaces deeply indented ; they are laid upon a 
beam, padded with wool, are shaved down until the de- 
pressions caused by the seeds become very slight and 
uniform. First steep the skins in water, and afterwards 
in a warm alkaline lye ; pile them upon each other while 
still warm and moist. By this means the parts indented 
by the pressure of the seeds regain their natural elasticity 
and not having lost substance by the shaving of the rest 
of the skins, they rise to or above the surrounding level, 
and form the peculiar grain of the shagreen ; after this, 
cleanse the skins by salt brine and dye them. 
38 



594 CURRYING. 

Green color is given to shagreen by passing over the 
flesh side a concentrated solution of sal ammoniac, strew- 
ing it over with copper filings, rolling it up with the 
same side inward, and pressing each skin for 24 hours 
with a heavy weight. The sal ammoniac dissolves enough 
copper to give the skin a beautiful sea-green color. 

Blue color is obtained with indigo dissolved in a solu- 
tion of soda with lime and honey. Black with copperas 
and nutgalls; red with cochineal. Pure white is ob- 
tained by dressing the strips first in an alum solution, 
then in wheat dough, and washing away the latter with 
lime-water. 

The preparation is completed by greasing, carefully 
working in hot water, currying with a blunt knife and 
drying. 

Shagreen is rendered very hard by drying, but it softens 
in water, and in that state will take any shape given to 
it, and is used by sheath makers for the cases of specta- 
cles, surgical and mathematical instruments. 

An imitation of shagreen has been made so much like 
the genuine article, that it is impossible to distinguish 
the difference. For this purpose sheep or goat-skins are 
used. Deprive them of hair in the lime pits, steep them 
in water, flesh and soak again ; rub them well down upon 
the horse with a hard polished piece of wood, after which 
they steep them a third time, beat out and trim them 
on both sides. Then steep them for two hours in a 
bath made of a bucket full of tan for fifty skins, mixed 
with enough water to cover the skins. An hour after 
a bucket half full of the same is thrown in, and another 
at the end of an hour and a half After this, keep them 
in tan pits eight days, remove them, wring out, and re- 
duce the thickness with the round knife applied upon 
the horse. Dry them partially, stretch in the direction 



PARCHMENT. 595 

of the length, cut in half, blacken in the usual manner 
and dry. 

The grain is given to this shagreen by means of copper 
plates engraved in imitation of the roughened surface 
of the real article. These plates, previously warmed, 
are placed upon the skins and then subjected to the 
action of a press. 



CHAPTER CXXXV. 

PARCHMENT. 

Parchment is the invention of Eumenes, King of 
Pergaraus, in Asiatic Turkey, about 200 years before 
Christ. It was known in early times, as Pergamena, and 
was used, on account of its great durability, for records 
and valuable manuscripts, and as a substitute for the 
papi/rus, or writing paper of the ancient Egyptians. The 
finest quality, made from thin and perfect skins, and 
prepared by very careful manipulation, is called vellum. 

Fine parchment, for writings, is made from the skins 
of calves, kids, stillborn lambs, sheep, and she-goats; 
but an inferior quality, for drum-heads and battledores, 
is prepared from the skins of he-goats, calves, wolves, 
and asses. Pig-skin is also sometimes converted into 
parchment for bookbinders' use. The operations are 
nearly the same, throughout, for all the varieties, but 
are more delicate for the finer quality. 

The skins above mentioned are those generally em- 
ployed for this branch of manufacture, but all other thin 
skins are applicable ; and sometimes the thinner halves 
of thick hides, split by machinery, are dressed* by this 
process. 



596 CURRYING. 

" The skins, after having been soaked, limed, shaved, 
and well washed, must be set to dry in such a way as to 
prevent their puckering, and to render them easily 
worked. The small manufacturers make use of hfiDops 
for this purpose, but the greater employ a horse, or stout 
wooden frame. This is formed of two uprights and two 
crossbars, solidly joined together by tenons and mortises, 
so as to form a strong piece of carpentry, which is to be 
fixed against a wall. These four bars are perforated 
throughout with a series of holes, which are fitted with 
very smooth and slightly tapered box-wood pins. Each 
of these pins is transpierced with a hole like a violin 
screw, by means of which the strings used in stretching 
the skin may be tightened. Above the horse, there is a 
shelf for such tools as the workman may need at hand. 
In order to stretch the skin upon the frame, large or 
small skewers are employed, according to the size of 
the piece which is to be attached to it. Six holes are 
made in a straight line to receive the larger, and four to 
receive the smaller skewers, or pins. These small slits are 
made with a tool like a carpenter's chisel, and of the 
exact size to admit the skewers. The string round the 
skewer is affixed to one of the bolts in the frame, which 
is turned round by means of a key, like that by which 
harps and pian6s are tuned. The skewer is threaded 
through the skin when in a state of tension. 

" Everything being thus prepared, and the skin being 
well softened, the workman stretches it powerfully, by 
means of the skewers; he attaches the cords to the 
skewers, and fixes their ends to the iron pegs, or pins. 
He then stretches the skin, first with his hand applied 
to the pins, and afterwards with the key. Great care 
must bl taken that no wrinkles are formed. The skin 
is usually stretched more in length than in breadth, from 



PARCHMENT. '597 

the custom of the trade ; though extension in breadth 
would be preferable, in order to reduce the thickness of 
the part opposite the back bone. 

" The workman now takes the fleshing-tool which is 
a semi-circular double-edged knife, made fast into a 
double wooden handle, seizes it in his two hands so as to 
place the edge perpendicularly to the skin, and pressing 
it carefully from above downwards, removes the fleshy 
excrescences, and lays them aside for making glue. He 
now turns round the horse upon the wall in order to get 
access to the outside of the skin, and to scrape it with 
the tool inverted, so as to run no risk of cutting the 
epidermis. He thus removes any adhering filth, and 
squeezes out some water. The skin must next be ground. 
For this purpose, it is sprinkled upon the fleshy side 
with sifted chalk or slaked lime, and then rubbed in all 
directions with a piece of pumice-stone, four or five 
inches in area, previously flattened upon a sandstone. 
The lime soon becomes moist from the water contained in 
the skin. The pumice-stone is then rubbed over the 
other side of the skin, but without chalk or lime. This 
operation is necessary only for the best parchment or 
vellum. The skin is now allowed to dry upon the frame, 
being carefully protected from sunshine and from frost. 
In the warm weather of summer, a mwst cloth needs to 
be applied to it from time to time, to prevent its drying 
too suddenly; immediately after which the skewers 
require to be tightened. 

" When it is perfectly dry, the white color is to be re- 
moved by rubbing it with the woolly side of a lamb-skin. 
But great care must be taken not to fray the surface ; a 
circumstance of which some manufacturers are so much 
afraid as not to use either chalk or lime in the polishing. 
Should any grease be detected upon it, it must be re- 



598 CURRYING. 

moved by immersion in a lime-pit for ten days, and by 
then stretching it anew upon the horse, after which it is 
transferred to the scraper. 

"This workman employs here an edge tool of the 
same shape as the fleshing-knife, but larger and sharper. 
He mounts the skin upon a frame like the horse above 
described ; but he extends it merely with cords, without 
skewers, or pins, and supports it generally upon a piece 
of raw calf-skin, strongly stretched. The tail of the skin 
being placed towards the bottom of the frame, the work- 
man first pares off, with a sharp knife, any considerable 
roughnesses, and then* scrapes the outside surface ob- 
liquely downwards with the proper tools, till it becomes 
perfectly smooth. The fleshy side needs no such opera- 
tion, and, indeed, were both sides scraped, the skin would 
be apt to become too thin, the only object of the scraper 
being to equalize its thickness. Whatever irregularities 
remain, may be removed with a piece of the finest 
pumice-stone, well flattened previously, upon a piece of 
close-grained sandstone. This process is performed by 
laying the rough parchment upon an oblong plank of 
wood, in the form of a stool ; the plank being covered 
with a piece of soft parchment stuffed with wool, to form 
an elastic cushion for the grinding operation. It is 
merely the outside surface that requires to be pumiced. 
The celebrated Strasburg vellum is prepared with re- 
markably fine pumice-stones. 

'' If any small holes happen to be made in the parch- 
ment, they must be neatly patched, by cutting their 
edges thin, and pasting on small pieces with gum-water. 

" Parchment is colored only green. Boil eight parts 
of cream of tartar and thirty parts of crystallized verdi- 
gris in five hundred parts of rain-water ; and, when this 



PARCHMENT. 599 

solution is cold, pour into it four parts of nitric acid. 
Moisten the parchment with a brush, and then apply 
the above liquid evenly over its surface. Lastly, the 
necessary lustre may be given with white of eggs, or 
mucilage of gum Arabic." 



600 CURRYING. 



SECTION X. 

PATENT LEATHER. 

The fabrication of varnished leather, or patent leather, 
has reached such a development in France within the last 
thirty years that this kind is exported to every country. 
This fabrication is not difficult, all that it requires is 
care and dexterity. There are several processes, but we 
think it only necessary to describe in detail the process 
now most usually followed. 



CHAPTER CXXXYI. 

FABRICATION OF THE PATENT LEATHER. 

The glazing of leather comprises two distinct opera- 
tions : — 

1st. The preparation of the surface. 2d. The var 
nishing. 

The object of the preparation of the surface is to close 
the pores of the leather, and make a proper ground by 
repeatedly rubbing the surface with pulverulent sub- 
stances and incorporating them with it. 

The object of the varnishing is to obtain a soft, supple, 
and bright coat, unalterable by rubbing. 

To prepare the surface, incorporate pulverulent matters 



FABRICATION OF THE PATENT LEATHER. 601 

which have the property of forming a mastic in the pores 
of the skin, such as cTiaXk^ ochre, lampblack, etc. 

In the varnish, on the contrary, no material used 
must destroy the transparency and brightness. 

The basis of both preparations is siccative linseed oil, 
prepared as follows : — 

For 25 galls, of oil, take — 
20 lbs. of lead, 
20 lbs. of litharge, 
and boil them together until reduced to a syrupy con- 
sistence. 

This composition is then intimately mixed with ochre 
or chalk, according to the fineness of the skin to be pre- 
pared, and is uniformly spread on either sides of the 
leather with appropriate tools. 

Three successive coatings are given at such intervals 
of time as will permit each coating to dry, when the 
surface is rubbed with pumice-stone. A number of thin 
coatings are applied in the same manner, and rubbed 
down until perfectly uniform, and of sufficient thickness 
to prevent the varnish from penetrating the leather, by 
which its qualities would be injured and its structure 
rendered hard and brittle. The oily substance of the 
preparation and of the varnish should merely penetrate 
deeply enough into the leather to make the composition 
of which it is the basis adhere closely to it. 

The foundation for the varnished surface being thus 
laid, a mixture of the above preparation without, how- 
ever, the addition of ochreous or other earthy matters, and 
well rubbed up with fine ivory black and enough spirits 
of turpentine to make it flow smoothly and easily, is laid 
on by means of a fine brush, three or four successive 
coatings being applied. By this means a black ajid 



602 CURRYING. 

shining, pliable surface is obtained, over which, as soon 
as it is perfectly dry, the varnish may be applied. 

After the application of each coating, the leather is 
dried, by hanging it up, or better, laying it out upon 
frames or racks in the drying room. Before varnishing, 
it is customary to give a polish to the surface by rubbing 
it over with a piece of 'woollen stuff and the finest kind 
of pumice-powder or tripoli. 

The varnish is thus prepared : Take 
Oil prepared as above 20 lbs. 
Asphaltum, 1 lb. 

Thick copal varnish, 10 lbs. 
Spirits of turpentine, 20 " 

The asphaltum and oil, being mixed together, are 
heated, then the varnish and spirits of turpentine are 
added, constantly stirring until the mixture is perfectly 
homogeneous. The asphaltum can be substituted by 
Prussian blue or ivory black. Leave the varnish to 
settle in a warm place for two or three weeks before 
using it. 

During and after the varnishing, be careful to avoid 
dust falling on the prepared skins. 

The temperature of the oven varies from 133° to 167° 
according to the nature of the leather and varnish. 

The tint of color of varnished leather varies with the 
coloring material which has been added to the varnish. 
Asphaltum gives it a reddish hue, Prussian blue a green- 
ish-blue metallic tint, and ivory black a pure brilliant 
black lustre. 

Some manufacturers add to the litharge employed for 
boiling the oil, red lead, ceruse, powdered cuttlefish-bone, 
oxide of manganese, and various other metallic salts or 
oiiides. 

The success of the process depends very much upon 



didier's and other processes. 603 

the care with which the skins prepared with it have 
been selected, tanned, and curried. It is very necessary 
that the dubbing should have been applied to them with 
great uniformity, and only in small quantities, for other- 
wise the surface will soon become tarnished and blotted. 



CHAPTER CXXXVII. 

DIDIER'S AND OTHER PROCESSES. 

Heat lampblack in a close vessel, and mix it with 
linseed oil varnish until the mass becomes sufficiently 
liquid to flow. Apply two coatings to the leather and 
let it dry. Mix then this varnish with an equal quan- 
tity of copal varnish and give another coating to the 
leather. As soon as this last coating is dried, polish the 
leather with a felt charged with finely powdered pumice 
stone ; then pa§s on the leather a waxed sponge, wipe 
with a cloth, and then give the polish. For this purpose 
rub on a slab one part of copal varnish with lamp- 
black, and give to the leather five or six coatings of this 
mixture with a brush. Dry, rub the leather with pum- 
ice stone, and give again two coatings of copal varnish. 

White polished leather. — Rub ceruse with white oil var- 
nish, and apply two coatings on the leather. Then rub 
Krem's white at first with water, let it dry and rub it 
with white copal varnish, give three or four coatings, 
and polish as above. 

Bed polished leather. — The first coating is given with 
shellac mixed with spirit of turpentine and the second 
with the same lac in copal varnish. This latter is pre- 
pared by dissolving one part of copal in two parts of 



604 CURRYING. 

turpentine and adding to this solution an equal quantity 
of linseed oil varnish. 

Blue polished leather. — Give a first white coating with 
ceruse mixed with oil varnish, then a blue coating with 
Prussian blue mixed with copal varnish. 

Yellow polished leather. — Yellow requires a white 
leather prepared by boiling it in a copper vessel con- 
taining a solution composed of fustic wood, lye, cochi- 
neal and alum ; pass this liquid through a cloth, give a 
coating to the leather, and when dried, apply the copal 
varnish. If no white leather is at hand, give a first bot- 
tom with light yellow ochre and ceruse mixed with ordi- 
nary varnish. The second coating is given with the same 
color mixed with copal varnish. When dry, polish the 
surface, and apply three coatings of yellow cassel mixed 
with copal varnish. 

Polished leather of leather color. — Apply a coating of a 
mixture of yellow ochre, white lead, and oil varnish ; 
when dry, polish. Give a second coating with Turner's 
yellow mixed with copal varnish. 

Black Lacquer for Shoes and Leather Worh. 

Mix four ounces of shellac and half an ounce of the 
finest lampblack in a stone bottle with 1 1 pint of strong 
alcohol, close the mouth of the bottle with a damp blad- 
der. Add nothing more to the mixture for twenty-four 
hours, but shake it often in that time. Then pierce a 
hole in the bladder with a needle, and place the bottle in 
hot water, and let it stand half an hour, taking it out 
often to shake it. Unfasten the bladder, pour an ounce 
of Venetian turpentine in the bottle, close up the mouth 
again, and place it once more in hot water. The bottle 
should be kept always corked, and it requires to be 
shaken before using the contents. 



didier's and other processes. 605 

Process for varnishing Leather fur BellSy etc. 

The varnish for leather is the same as for carriages, 
except that it contains less copal, and that the oil used 
in the varnish for certain coarse articles should be a little 
decomposed. 

After having dressed and scraped the leather to be 
varnished, apply upon the flesh side a thin coat of glue 
water, to which has been added about one ounce of boiled 
linseed oil. The leather when dried is polished, and suc- 
cessive coatings applied until it becomes very smooth. 
Then mix one part of strong dying oil, and one part of 
copal varnish in an iron vessel, add well pulverized 
lampblack and spirits of turpentine, and set the whole 
over a fire. The leather which during this time has been 
kept in a closet artificially heated, is now stretched upon 
a table, a very thick coat of the mixture quickly laid on 
with a flat brush, immediately placed in a warm closet 
and allowed to dry slowly. When dried it is polished 
with pumice stone, or, which is better, with charcoal 
finely powdered and sifted. A second coat is applied in 
the same way, and the operation finished with a third 
coat which should be very lightly laid on and be very 
smooth. The leather is now dried without polishing. 



606 



CURRYING. 



SECTION XI. 

WATER-PROOF LEATHER. 

Many processes have been proposed to render leather 
water proof. Those processes which rest upon the in- 
crease of the density of the matter by the use of fat, 
resinous or gummy matters present no great interest; 
nevertheless for the satisfaction of the reader we shall 
give a few of them. 



CHAPTER CXXXVIII. 

PROCESS OF J. SMITH AND J. THOMAS. 

i. 

Macerate the leather you want to render water proof 
in water for twenty-four hours ; then press it between 
two iron cylinders, and let it dry in the air for five 
days. Then mix the following liquor : — 

Linseed oil . . . .4 pints 



Olive oil . . 


. 2 " 


Spirit of turpentine 
Castor oil . 


. 1 " 
2 " 


Beeswax 


8 ounces 


Pitch 


4 " 



Boil all these substances over a gentle fire in an earthen 
vessel, and during the ebullition dip in the leathers which 
leave more or less time, according to their nature. 

Sole leather must stay about twenty minutes. Calf 



PREPARATION TO RENDER LEATHER WATER-PROOF. 60 T 

and cow-skins about ten minutes. Those leathers thus 
prepared are drained and pressed between two iron cyl- 
inders covered with leather. Dry then in an oven heated 
at 77 to 86°, press them again and put them anew in 
the oven. 



CHAPTER CXXXIX. 

NENORY'S PREPARATION TO RENDER LEATHER WATER 
PROOF AND IMPERVIOUS. 

The preparation of this compound is made as fol- 
lows : — 

Preparation of Siccative Oil. 

Take 100 lbs. of linseed oil and 13 lbs. of litharge; boil 
them together at a moderate heat for several hours, 
until the oil is reduced to the two-thirds. 



Take— 



Preparation of the Elastic Oum. 



Old linseed oil 
White wax 
Glue . 

Verdigris 
Water 



U lbs. 

1 lb. 
5| lbs. 
4 oz. 

2 qts. 



Melt the whole at a gentle heat, in an iron vessel. 



until it forms a homogeneous mass. 



608 



CURRYING. 



Preparation of 


the Compound. 


Take- 








Siccative oil prepared as ab 


ove 


. 


100 lbs. 


Gum prepared as above 








3 " 


Beeswax 








. 10 " 


Spirit of turpentine . 




. 




13 " 


Balsam of Peru 




, 




2 " 


Oil of thyme 








2 " 


White pitch 








6 " 


Melt the whole in an iron vessel at 


a gentle heat 


without boiling ; then pour 


this 


composition in the bot- 


ties which must keep it. 











Process of using the Composition. 

Put the bottle near the fire, so to render it fluid with- 
out heating it. After having well dried and brushed the 
leather, pass the composition over it with a little sponge 
or a brush, and during the operation expose the leather 
to the sun or to a gentle heat. "When the leather is 
dried, repeat the operation until saturated. If it stays 
on the leather, some composition which has coagulated, 
rub it with a rough cloth, then apply any kind of black- 



ma:. 



CHAPTER CXL. 



DEANE'S PROCESS FOR RENDERING LEATHER 
IMPERVIOUS. 

First Composition. 

1. Take : Linseed oil, rape-seed oil, and neats-foot oil, 
251 gallons; boil until reduced to 21^ gallons. 

2. Take: Mutton or tallow sUet; melt it at a gentle 
heat ; pass it through a sieve ; boil it one hour in water. 



PROCESS FOR RENDERING LEATHER IMPERVIOUS. 609 

filter and let it cool, and put the cakes on cotton cloth 
to absorb the dampness. 

3. Take of the grease prepared above (2) 34 i lbs. and 
34 i lbs. of fresh wax; melt them together, and keep 
them at a temperature of 158°, until the whole is well 
incorporated. 

4. Take 2 lbs. and 2 drs. of India-rubber in shreds, 
that you dissolve in 8 quarts of rectified spirits of tur- 
pentine at a temperature of 248°, over a sand-bath. 

5. Take 10 lbs. and 1 drachm of Burgundy pitch, 
that you melt with 2h gallons of spirits of turpentine at 
194°, over a water-bath ; leave this mixture to cool until 
it reaches 158°, then add it to the above mixture, and 
stir the whole until well incorporated. 

Second Composition. 

1. Take oil, grease,' and melted wax; mix as above 
at a temperature of 158°. 

2. Take 4 gallons of turpentine, in which you dis- 
solve 10 lbs. 1 drachm of yellow rosin over a sand-bath, 
at a temperature of 200°. 

Wh^n the mixture thus prepared has cooled to 158°, 
add the resinous composition to that of oil, grease, and 
wax ; stir the whole until cold. 

Third Composition. 

Take 21 i gallons of pure whale oil, and from 13 to 17 
lbs. of India-rubber shreds; heat them together at 194° 
to 240°, which is sufiicient to operate the dissolution of 
the India-rubber. 

Fourth Composition. 

Take rectified spirits of turpentine, sufiicient to cover 
13 or 17 lbs. of India-rubber shreds; boil gently over a 
39 



610 WATER-PROOF LEATHER. 

sand-bath heated at 240°, until the entire dissolution of 
the India-rubber; add to this composition 21 gallons of 
pure whale oil at 194°, and keep thus until the mass is 
fluid and united; let the temperature fall to 158°; add 
82^ lbs. of fresh wax; stir the ^hole until cold. 

Application of the Composition. 

The first and second compositions are used for skins, 
and the third and fourth for leathers. 

The skins are saturated with the first or second com- 
position, by spreading them in a vessel which communi- 
cates with a kettle in which is the composition. Intro- 
duce the composition heated from 144° to 212° in the 
vessel containing the skins until entirely covered ; leave 
them thus two or three hours. The skins are then 
withdrawn, and submitted to a current of air gently 
heated, until dry. In this process hydrostatic pressure 
or vacuum can be used the same as we have seen for 
tanning. 

The leathers, if thin, are impregnated with the third 
composition ; if thick, with the fourth. They are placed 
on a metallic plate, heated at 104°, and they are covered 
with the composition by using a brush. The saturation 
is achieved by rarefying the air contained in a room 
purposely constructed. 

You operate on leather by exposing it in a room at a 
temperature of 100 to 120°; then one or two hours 
after, when warm, coat them with one of the above 
compositions until well saturated ; place them in a room 
at the ordinary temperature, and leave them iu until 
dry. 



DIFFERENT PROCESSES. 611 



CHAPTER CXLI. 

DIFFEEENT PEOCESSES. 

Cheap Method of making Leather Water-proof. 
Melt together in an earthen pipkin 

Tallow 2 lbs. 

Lard 1 lb. 

Turpentine . . . . h " 

Beeswax . . . • i " 

Dry the leather well and warm it. Eub the composi- 
tion into them with a piece of tow dipped into it, the 
articles being held near. a hot fire until they have had 
rubbed on them as much as they can take up. 

There is another mixture much used by fishermen, 
which consists in melting together 

Beeswax . . . . 1 lb. 
Rosin ..... ^ " 
Suet i " 

Jenning's Process. 

Dissolve any metallic soap in an equal quantity of raw 
linseed oil, and immerse the leather in that solution 
heated at 225°. When the latter has become cold, take 
the leather out and dry it in the air. Forty-eight hours 
are sufficient for the whole process. 

Canvas and similar fabrics can also be rendered water- 
proof by the following process : — 

Dissolve 

Soft soap .... 100 lbs. 
In boiling water ... 30 galls. 

Heat the solution to 212° with 66 lbs. of sulphate of zinc. 



612 WATER-PROOF LEATHER. 

An insoluble salt of zinc is formed, while the sulphate 
of potash dissolves in water ; the metallic soap rises on 
the surface of the liquor, and is boiled in fresh, water to 
purify it. 

Boil 5 lbs. of pearlash with 50 galls, of raw linseed oil, 
until the mixture assumes a soapy appearance, and to 
it while hot add, stirring all the time, 



Sugar of lead 


^ lbs. 


Litharge 


2 " 


Red lead 


4 " 


Black rosin 


. 21 " 



Boil one hour, constantly stirring, and at the end of that 
time add 30 lbs. of the metallic soap. 

Add to the mixture two gallons of a liquor made by 
dissolving India-rubber, 24 ounces in one gallon spirit 
of turpentine. Allow the mixture to cool to 160°, and 
apply it with a brush. Two or three coatings are suffi- 
cient, but there must be an interval between each coating 
to insure a perfect drying. 



PART lY. 

HUNaARY LEATHER. 



SECTION XII. 

This method of preparing skins, analogous to tanning, 
was originally introduced into Hungary from Senegal. 
It was imported into France, in 1573, by a tanner of the 
name of Boucher. In the next century the great Colbert 
established a manufactory at St. Cloud, in which the 
process was adopted; and, in 1702, this establishment 
was removed to La Roquette, in Paris, in which it was 
in successful operation for a long time. 

The process of manufacturing Hungary leather is a 
rapid one ; it consists in impregnating strong hides with 
alum, common salt, and suet ; and is almost the same 
as when first introduced from Hungary. The only im- 
provement we know is the one introduced by Curaudeau, 
of which we shall speak hereafter. This kind of leather 
is manufactured all the year round, measures being 
adopted to counteract any injurious influences the tem- 
perature might exert upon it. 

The workshop is divided into two parts : — 

1st. A shed on the bank of a river in which are placed 
the beams, the fleshing and paring-knives, and the scrap- 
ing-stones. In a corner is a furnace to prepare the so- 
lution of alum, and near it are two tubs to immerse the 
skins. Besides this a number of ordinary tubs is re- 
quired. 



614 HUNGARY LEATHER. 

2cl. The other part of the factory consists of a room 
6 feet high by 15 feet square, perfectly tight, so as to 
retain the heated air. In a corner of this room is a fur- 
nace, fed with fuel through a door opening externally, 
upon which is placed a copper kettle, capable of con- 
taining 160 lbs. of tallow. In the middle of this kind 
of oven is a square stove, upon which an iron grating, 
three feet square, is placed for the rec§ption of coals. 
On either side of this oven, and occupying its whole 
length, are large tables upon which the skins are greased. 
The upper part below the ceiling is filled with poles, 
upon which the leather is hung in order to dry. The 
door of this room fits closely to its joints, so as to pre- 
vent the entrance of cold air. 

The most suitable hides for Hungary leather are 
strong ox-hides, but bull and cow-skins can be prepared 
in the same manner. The process is rapid, and may be 
completed in two months or less time. These hides can 
scarcely be compared with those tanned and curried in 
the ordinary way, since they consist of the original tis- 
sue of the skins condensed and slightly altered in cha- 
racter by the process to which they are subjected, but 
not converted into true leather by combination with 
tannin. Moreover, they are employed for different pur- 
poses. 

The chief operations to which hides are subjected are 
the following: — 

1. The river-work, 6. Treading out, 

2. Aluming, 7. Tallowing, 

3. Second aluming, 8. Flaming, 

4. Drying, 9. Airing, 

5. Stretching, 10. Marking and piling. 

Before describing these operations we shall say a few 
words on the diiBferent greases employed in this process. 



GREASE AND ANIMAL OILS. 615 



CHAPTER CXLII. 

GEEASE AND ANIMAL OILS. 

These substances of animal origin are white or yel- 
lowish, sometimes odorless, sometimes with a strong 
odor. The consistence is variable ; the taste is sweet, 
lighter than water, without action on litmus, more or 
less fusible, alterable in the air, insoluble in water, solu- 
ble in alcohol which dissolves the oleine. 

Greases are composed of two principles, one liquid, 
the oleine, the other solid stearine and margarine ; and 
it is according to the proportions of the latter that de- 
pend the fusibility of the grease. 

Lard 

Is white, inodorous, soft; melts at 80°. 6, is insoluble in 
water; 100 parts of boiling alcohol dissolve 2.80 which 
are oleine. Treated by caustic alkalines, it is converted 
into glycerine and oleate, margarate, and stearate, of 
these bases, which by their union constitute the soaps. 

According to M. Chevreul, lard is composed of oleine 
and stearine, and its elementary constituents are repre- 
sented as follows : — 

Chevreul. Saussure. 

Carbon . . . . • . 19.098 T8.843 

Hydrogen .... 11.146 12.182 

Oxygen 9.756 8.502 

Nitrogen .... 0.473 



100.000 100.000 



This substance is employed in currying, Hungarying 
etc. 



616 HUNGARY LEATHER. 

Mutton Suet. 

This grease is firmer than the above, odorless, insipid ; 
brittle when pure ; insohible in water, and very mode- 
rately so in alcohol. 100 parts of alcohol dissolve only 
2.26 of oleine. 

According to Mr. Chevreul it is composed of oleine, 
stearine, and a small quantity of hircine. Its element- 
ary principles are as follows : — 

Carbon .... 78.996 
Hydrogen . . . . 11.700 
Oxygen .... 9.304 

100.000 

Beef Tallow. 

This tallow has a light yellowish color. It is firm, 
brittle, fusible at 104°, insoluble in water, soluble in boil- 
ing alcohol. Its properties and composition are the same 
as the above. 

Medullary Beef Tallow. 

This kind of grease is of a bluish-white color, fusible 
at 113°. It is composed of 

Solid grease . . . . 76 
Oil 24 



100 



The oil has a very disagreeable odor, and is nearly 
colorless. 

Fish Oils. 

From fish a kind of greasy fluid is obtained which 
we call oil, giving to it the name of the fish it is extracted 
from. While spermaceti is not, properly speaking, an 
oil, however, as it has some of its characters, it may 
be included among them. 



GREASE AND ANIMAL OILS. 617 

Dolphin Oil. 

This oil is extracted from the dolphin, Delphinus globi- 
ceps. Its color is lemonish. Its odor similar to that of 
the fish. Its specific gravity 0.9178. 100 parts are 
dissolved in 100 parts of alcohol at 0.812, at a tempera- 
ture of 158°. Its solution has no action on litmus. This 
oil exposed to a cold of 26°.6 separates into a crystal- 
line substance and an oil which solidify at 28°.4. The 
crystalline matter is much similar to cetine. It is 
formed of oleine, phocenin, and a little phocenic acid. 

Porpoise Oil 

Is extracted as the above, from the Delphinus phoccena. 
It is yellowish. Its specific gravity 0.937 ; without action 
on litmus, soluble in alcohol, and saponifiable in alkalies. 
It is composed of oleine, phocenine, an orange-red prin- 
ciple, an odoriferous principle, and phocenic acid. 

Different Fish- Oils. 

This oil belongs to different fishes, particularly to the 
whale. The oil is separated by pressure from the solid 
grease. It is fluid, sometimes colorless, sometimes of a 
reddish-brown with a disagreeable odor. According to 
Mr. Chevreul, it is formed of oleine, stearine, two odorife- 
rous and coloring principles. It possesses a great simi- 
larity to fixed oils. Its elementary principles, accord- 
ing to Berard,. are — 

Carbon . . . . I^M 

Hydrogen * . . . 14.35 
Oxygen .... 6.00 

100.00 



618 HUNGARY LEATHER. 

Process hy wMcli to give to a mixture of different Oils 
and Greases the properties of Fish Oils. 

Take the inferior qualities of seed-oils and boil them 
several times in a kettle to separate the aqueous, earth v, 
and acid parts. Boil putrefied horse guts or bad fishes. 
Mix these two substances in the kettle. Add seed oils, 
horse-fat, residuum of seed oils purified by sulphuric acid, 
and at last whale or cod-liver oil. Stir this mixture for 
twenty-four hours in the kettle. Leave to settle ; pass 
through a skimmer. You obtain thus an oil as good as 
cod-liver oil, which is the best. 

Process for rendering Vegetable Oils fit to take the place 

of Fish Oils. 

Melt in a kettle over a gentle fire 16 lbs. of lard, 
mixed with 100 lbs. of nut oil or linseed oil, or any 
other seed oils. Stir well, till the mass is homogeneous. 
Take ofi" of the fire, and when partially cold, pour in it 
while stirring four ounces of sulphuric acid.' 

This oil has the same properties as fish oils. 



CHAPTER CXLIII. 

EIVER WOEK. 

The first operations are similar to those of tanning 
and tawing. The hides are washed, cut in two, scraped 
upon the horse with a round knife, and are then care- 
fully and slightly washed; the fat and flesh alone 
being removed. 

Afterwards scrape off* the hair from the hides, by plac- 
ing them upon a bed of other skins folded double and so 
disposed upon the horse as to present a smooth and per- 



ALUMING THE HIDES. 619 

fectly uniform surface. This operation must be carefully 
conducted to avoid injuring the surfaces, and it will take 
one day for a skilful workman to separate the hair from 
eight or ten hides. Then soak the skins in the river for 

Fig. 150. 




twenty-four hours, or in vats for three days, changing 
the water twice a day in summer and once in winter. 
If you soak in running water, drive a stake into the 
ground, and fasten the hides to it by a cord passing 
through the hide holes, or those left by the removal of 
the horns. 



CHAPTER CXLIV. 

ALUMING THE HIDES. 

The aluming is the most important preparation to 
which Hungary leather is submitted. Not only does it 
prevent the putrefaction of the hides, but effects a chemi- 
cal change in them, by which they are rendered stronger 
and more substantial. The exact nature of this chemical 
influence is not known yet, but the supposed reaction is 
as explained under kid-leather. 

The hides are first treated with a mixture of alum 
and salt, by which a portion of the sulphate of alumina 



620 



HUNGARY LEATHER. 



is transformed into chloride of aluminium. This salt 
softens the effects of the alum, attracts moisture of the 
atmosphere, and preserves the suppleness of the leather. 
Generally, the manufacturer works nine hides at a time. 
When the skins are ready to be alumed, dissolve alum 
and salt in a kettle disposed on a furnace. This kettle 
is round below, and of a size according to the quantity 
of skins to be treated. An ordinary kettle is 14 inches 
deep in the middle and about 22 inches diameter, and is 
large enough to alum nine skins at a time. 

Fig. 151. 




The proportions of alum and salt used are for each skin — 

. 6 lbs. 



Alam 

Salt 

Water 



^2 



. T^ galls. 

Heat the water at about 122°, throw in it the alum and 
salt, and stir until dissolved. 

When the solution is ready, put the skins in two 
vats, 4 feet 10 inches long, 3 feet wide, and 27 inches 
deep. 

When nine hides or eighteen strips are worked to- 
gether, the whole is divided into three lots of three skins 
each. Three strips are placed in each vat, bfeing prepared 
upon each other with the hair side up, and so arranged 
that the head of the second one is above the tail of the 
first, and so on. It may occur that the leathers are very 
strong and large, and require much care, then instead of 
three lots you make four. 



ALUMING THE HIDES. 



621 



When the leathers are thus disposed you alum them. 
For this purpose take in the kettle two or three pailfuls 

Fig. 152. 




of the alum solution. This solution must be tepid, for if 
too warm it will burn the leather. Heat gradually, so 
that the last is warmer than the one before used. Pour 
this water on the hides. Then a man beats them with 
his feet. This operation is renewed three times. Each 
time the workman beats with the feet, twice the backs 
and once the bellies. Each three turns forms what is 
called one water. During this operation another man 
puts tepid water in the second vat, and disposes the strips 
as above indicated. 

This first water done, the man passes in the second 
vat and begins the same operation. For each three skins 
you give four waters in the same manner, but each time 
the liquor must be warmer. 

After the fourth water fold the hides double and de- 
posit them in tubs 2 feet diameter and 2 feet 
deep. Fill this tub with alum water which 
has been used, and immerse the hides. Gene- 
rally, the hides are left in these tubs eight 
days, the position being changed every day 
or two. Some manufacturers leave them a longer time 
in winter, but no difference need be made in this respect 
between the seasons. 



Fig. 153. 




622 HUNGARY LEATHER. 



CHAPTER CXLV. 

SECOND ALUMING. 

The skins being removed from the tubs and well 
shaken to remove the folds, they are subjected to the 
same series of operations as in the first aluming. Steep 
them twenty-four hours in the same alum water, take 
them out and leave them to drain on planks arranged 
in a slanting position, so that the liquor escaping from 
the hides runs back into the vats. 



CHAPTER CXLVI. 

DRYING AND STRETCHING. 

When the hides are perfectly drained, make four holes 
in each strip, and thrust a stick through them ; the stick 
is supported by its two ends upon poles near the ceiling 
of the drying room. Suspend the hides and leave them 
till nearly dried. Take them down, lay them upon the 
floor, being folded double with the hair side within; a 
workman stretches all their parts and takes out the 
wrinkles, which have formed in them by forcibly drawing 
a stick 2 ft. long and about § of an inch in diameter, in 
every direction over the surfaces. Then pile up the 
hides, leave them a day or two in this state, suspend 
them upon the poles until thoroughly dried. 

During cold weather hang the hides for a time on the 
poles in the store-room, heated with charcoal. When 
sufficiently warm stretch and pile them one upon the 



TREADING OUT THE HIDES, 623 

other, and cover them with cloths to protect them from 
the cold. Thus prepared, this leather keeps as well as 
tanned leather, and it is only necessary to have dry 
winds, to avoid exposure to a hot sun, in order that it 
may not become so dry as to be worked afterwards with 
difficulty. 



CHAPTER CXLVII. 

TREADING OUT THE HIDES. 

The leather being dried, is softened and prepared to 
receive the tallow, by a peculiar method of stamping. . 
Erect a platform with planks slanting in one direction, 

Fig. 154. 




and supported upon cross pieces 12 to 13 inches a part. 
The hide to be worked is folded, double, with the hair 
side in contact, and a smooth stick of 
hard wood, 26 inches long and I of an '^' 

inch in diameter, is passed through. 

The workman wears thick soled shoes without heels, 
and stands upon the folded strip, laid upon the upper 



624 



HUNGARY LEATHER. 



part of the platform; and, holding on to a railing, he pro- 
ceeds to roll the stick by repeated stamping and shuffling 
movements of his feet from its first position to the edge 
of the strip. He repeats again and again, changing the 
position of the stick, and the hide is turned until every 
part is well tramped. He folds the leather in the oppo- 
site direction, so that the flesh side is in contact, and it 
is exposed again to the stamping process. He continues 
the operations until the pores become as soft and supple 
as it is possible to make them. Then he piles the strips 
upon each other for a time, and if not sufficiently dry, 
he exposes them to a hot sun or to the heat of the drying 
room ; then he treads them out a second time precisely 
in the same manner as before. 



CHAPTER CXLVIII. 

TALLOWING. 

The hides are impregnated with tallow in the store- 
room, and the tallow is melted in a boiler capable of 
containing 170 lbs. This boiler is 20 inches deep and 



Fig. 156. 




TALLOWING. 625 

35 inches in diameter, and is imbedded in the masonry 
of the furnace. 

In the middle of the store-room is a stove, massive, 
square, and large enough to put on it an iron grate 3 feet 
square ; the object of this grate is to support the lighted 
coal destined to. heat the room. 

Fig. 15T. 

H 1 1 i If I r l^ 
J 1 1 1 1 1 1 1 1 1 

J ill t II II rj- ' 
I I I I I III I I't 
.' / I I I I I I r k 
^irl I I I 1 1 f ff 
I I I I I I III '^ 
I I I I I I I r 
i I M I I I I I 

A heating apparatus has been proposed by Mr. Curan- 
deau. It consists of an oval shaped stove 2 feet high 
and 3 feet in diameter. The interior consists of a cast- 
iron hearth, paved at the bottom with bricks, and adapt- 
ed for burning wood. The smoke and heat ascend 
through a pipe 2 feet long and 5 inches in diameter, and 
are conducted into a vertical pipe 3 feet high and 11 
inches diameter. From the top of this two smaller 
•pipes diverge, and are connected with two other ver- 
tical columns, each two feet ten inches high and nine 
inches in diameter, which are placed at the side of the 
main column ; and with the lower ends of these two 
pipes a fourth horizontal one, placed two inches above 
the top of the stove, is connected, and into this the smoke 
and heat finally enter ; the former to escape through a 
chimney, and the latter to be given off to the air of the 
room. 

In the oven you suspend poles on which you put the 
leathers to warm them. On both sides are two large 
tables used to spread the hides when you tallow them. 
40 



626 



HUNGARY LEATHER. 



When the hides are ready to be greased, fill the boiler 
three-quarters full with tallow and heat it until melted. 



Fig, 158. 



^ 



Ly 



M 



S\ 




When it has attained a degree of heat a little above the 
melting point, it is ready for use. If the heat is too great, 
the draught must be lessened and lumps of cold tallow 
must be thrown in. While the tallow is being melted, 
kindle a fire upon the grate with a basketful of charcoal. 
As soon as the charcoal is kindled, fold double 24 to 
38 strips of hide according to the size, stretch them across 
the poles below the ceiling of the room, placing the 
largest and thickest the nearest to the fire. Then the 
workmen leave the stove-room, closing the door tightly 
behind them, in order to escape from the stifling vapors 
proceeding from the hides and the charcoal, and do not 
return until they are assured that the heating has been 
carried far enough. Then they air the room a little by 
opening the door, enter in with no clothing but short 
aprons, and examine the leather. When sufiiciently 
warm they observe a white appearance, beginning at the 
extremities and extending over the whole surface of the 
hides. As soon as this is the case, they remove the strips 
from the poles, and stretch them out upon each other, 
with the flesh side uppermost, on the table near the boiler. 
The thickest parts of the hides are placed nearest to the 




TALLOWING. 627 

boiler, and the smallest and thinnest strips are made to 
occupy the lowest position in the pile. 

Two men are employed in tallowing the hides. One, 
the nearest to the boiler, takes off the uppermost strip of 
the pile and folds it double, with the flesh side out, and 
the head placed upon the table, assures himself that the 
tallow is heated to the proper point. Then he takes a 
tallowing cloth or mop made with pieces of rags or blanket 
stuffs, a foot long, and tightly tied around a wooden handle 
six inches long, and, having immersed it in 
the boiler long enough for it to become satu- ^'&- ^^^* 
rated with the melted fat, rubs it over the 
head part of the flesh side until the half of 
the surface is sufficiently /e<i. 

He is assisted by other workmen with a similar mop, 
and when half of the leather is properly greased it is 
extended out at full length by the two workmen, and the 
whole of the flesh side is saturated with grease. Then 
the strip is turned over, and the hair side is greased with 
the tallow still adhering to the mops, which are not 
dipped again in the boiler, for fear of injuring the surface 
by the heat of the melted tallow. When greased through- 
out, lay the strip upon the table upon the opposite side 
of the room, with the flesh side up. The skins are in 
like manner successively greased and piled upon each 
other on the table until the end of the operation. 

It takes one hour to prepare thirty strips. Grease of 
inferior quality, such as the residuum of melted tallow 
and kitchen stuff, may be employed, and about 3 lbs. 
of it are required for each piece of leather. In the 
country they use sometimes 10 lbs. of tallow for one 
leather, i. e., 5 lbs. for each strip, but it is useless, as the 
skin does not absorb it all. 

There is no art in which the workmen are exposed to 



628 HUNGARY LEATHER. 

more fatigue and danger than those they are compelled to 
encounter while conducting the operations in the stove- 
room. They constantly inhale the suffocating vapors of 
the skins and melted tallow, and the dangerous oxide of 
carbon given off from the combustion of the charcoal ; they 
are exposed to the risk of suffocation or at least to great 
irritation in the lungs, while the profuse perspiration of 
the body predisposes them to take cold. Precautions must 
be taken for them to leave the room immediately after 
the charcoal fire is lighted, and not re-enter it until the 
atmosphere has become changed by a current of fresh 
air entering through the open door. 

They should not go into the room with full stomachs, 
but commence the operation three or four hours after a 
meal, and in quitting work should rub themselves down 
with a coarse towel before resuming their dress. Buzzing 
or tinkling noises in the ear, giddiness and headache, are 
regarded as premonitors of the dangerous effects of the 
inhalation of oxide of carbon, and upon the occurrence of 
this the men should immefdiately leave their work and 
go into the fresh air. 



CHAPTER CXLIX. 

FLAMING. 

Leave the hides for a time to absorb the tallow with 
which they have been impregnated, and cover them 
with cloth in order to prevent the unequal action of the 
fire upon them. Then kindle a fire upon the grate with 
a basket full of charcoal, leave the room, and after a 
lapse of half an hour, open the door to allow the gas to 
escape. The charcoal being in full combustion, two 



EXPOSURE TO THE AIR. 629 

men enter, take the uppermost strip off the pile, one by 
the head, the other by the tail, stretch it in every direc- 

Fig. 160. 




tion over the fire with the flesh side down, and continue 
this for about one minute. They extend the strip upon 
the empty table, the flesh side up, and repeat the same 
operation with the other strips. When the flaming is 
finished, they cover the new pile of hides with a cloth, 
and leave it so half an hour in summer, and three hours 
in winter. This operation is necessary for the complete 
penetration of the hides by tallow. Some manufacturers 
light a large fire in the room and keep the skins exposed 
to its heat with the door closed for half an hour or 
more. 



CHAPTER CL. 

EXPOSURE TO THE AIR. 

After the hides have remained in piles for about three- 
quarters of an hour, they are wiped on both sides with 
a dry rag or mop, to remove the excess of grease, and 
are hung in the air upon poles, the flesh sides up, and 
the heads and tails depending. They become firm if 
they are not exposed to the direct influence of the sun. 



630 HUNGARY LEATHER. 

In summer they should be tallowed shortly before sun 
down, so that when they are aired, they need not be ex- 
posed to the heat, but may be cooled by the night air. 
In winter this precaution is unnecessary. It is sufficient 
to air during the night in summer, and thirty hours in 
winter. 



CHAPTER CLI. 

WEIGHING.— MARKING.— PILING. 

The last operation consists in weighing, marking, and 
piling the leather. When dry, which takes place in one 
night in summer and in twenty-four or thirty hours in 
winter, they are piled and left so for a few days. A 
hide thus manufactured loses about half of its original 
weight, some less ; some lose three-fifths, so that a hide 
which from the butcher weighed 50 lbs. is sometimes re- 
duced to 20 lbs. 

When the leather is weighed, mark the weight in 
Roman characters on the tail, pile them up, and a few 
days after they are ready for the consumer. The room 
in which they are piled must not be too damp or too 
dry. This leather can be kept nine or ten months with- 
out alteration in the quality, but at last it will lose of 
its weight and suppleness and become dry and hard. 

In the summer season a hide of leather can be manu- 
factured in fifteen days ; but in winter it requires from 
three weeks to one month. 

Fine Hungarian leather is worth, in France, from 
twenty to twenty-two cents a pound ; a fine strip weighs 
from twenty-six to twenty-eight pounds, and measures 
nine feet by three. 



HUNGARY LEATHER MADE OF HORSE-HIDES. 631 

Alumed hides which have been dried can be kept a 
long time without alteration, and it is in that state that 
they must be kept when it is necessary to preserve them 
a long time in store after their manufacture. 



CHAPTER CLII. 

HUNGARY LEATHER MADE OF COW AND CALF-SKINS. 

Occasionally cow-skins are prepared by the Hunga- 
rian method, but they are depilated by liming instead of 
scraping. They are left in the lime-pits until the hair 
is ready to come oflT, when it is removed, and the skins 
being washed and scraped until the last remaining por- 
tions of lime have been separated, are prepared in the 
same manner as thick hides, excepting that before being 
tallowed they are not exposed for so long a time in the 
stove-room. 

The liming renders them spongy, and disposes them 
to absorb a larger quantity of alum and salt than ox- 
hides, in proportion to their weight. 

Calf-skins are prepared in the same manner, but absorb 
much less quantities of the materials used ; a large calf- 
skin requires about 1 lb. of alum, 8 ounces of salt, and 
1 lb. of tallow. 



CHAPTER CLIII. 

HUNGARY LEATHER MADE OF HORSE-HIDES. 

These hides are worked in the green state, and to pre- 
vent the inequalities of surface which would otherwise 
be found upon them, they are not thoroughly fleshed. 



632 HUNGARY LEATHER. 

but a part of the membranous substance is left upon 
their flesh sides. A horse-hide, thus prepared, weighs 
30 lbs. and used to be sold for $1.20 ; it is now worth 
from $2.40, to $3.00. 

The hides are first cut in half and put to soak for 12 
hours, then they are fleshed with a sickle-shaped knife, 
and depilated by means of lime, first for one day in an 
old pit, then they are withdrawn and piled up for two 
or three days, when they are put in a second and third 
lime-pit for three days. 

When depilated, soak them 12 hours in summer and 
24 hours in winter, occasionally stirring in order to re- 
move the lime. When clean, scrape them with the 
stone, and dress them upon the hair side with the round 
knife. Then roll them up from head to tail, and put 
them aside to drain six hours. 

They are trodden out in the vats, like other hides, 
with three alum waters, the tails and manes being beaten 
more forcibly than the other parts. A large horse-hide 
requires about 5 lbs. of alum and 2i lbs. of salt. 

After being stamped, place them in the tubs with alum 
water, let them remain in from two to eight days, and 
tramp them again in the same liquors. 

Drain and partially dry them, stretch them out with 
the hands, dry them entirely, and work them upon the 
platform as ox-hides, heat them upon the poles in the 
stove-room for from a quarter to half an hour, according 
to their degree of dryness ; when they are thus heated, 
they give ofi" a vapor so offensive as to be scarcely endu- 
rable. 

Tallow and finish them in the usual manner. They 
require half the quantity of grease which is used for ox- 
hides. The ordinary weight of a horse-hide thus pre- 
pared is 30 lbs., but they run from 14 to 60 lbs. 

This leather is often mistaken and sold with that 



kresse's process. 633 

prepared from ox-hides, but it is much inferior to the 
latter, being apt to harden and shrink and being much 
less firm and strong. 

A few donkey-hides are also prepared, but they give 
a bad leather, hard, brittle, horny, and difficult to work. 
Their preparation is the same as that of other hides, 
but they take very little tallow. Such a hide is gene- 
rally sold for 80 cents, and, when prepared, weighs from 
6 to 8 lbs., and is sold from 15 to 16 cents a pound. 



CHAPTER CLIV. 

M. KRESSE'S PEOCESS OF PREPAEING BLACK HUNGAEY 

LEATHEE. 

Mr. Kresse took a patent in 1836 for preparing black 
Hungary leather in the following manner : — 

Take, when fresh, the hides intended to be blackened, 
and spread over the flesh side a mixture of orpiraent 
and lime, and leave in contact for two hours. Then 
take the hair off, and pass for some days the hides in 
baths of tan, alum, and salt. Dry them partially ; soften ; 
supple, and dry them. Grease them with boiling tallow ; 
soak them in water; stretch them upon the table, and 
apply the color on the hair side. Rub over at first the 
surfaces twice with stale urine. The third and fourth 
applications consist of a color made with decoctions of 
three parts of logwood and one part of fustic ; the fifth 
and sixth of alder bark, iron rust, and nutgalls, mixed 
with lemon-juice. Being thus coated, dry the skins, 
and smooth them by stretching upon the table. 

To make the color of the last two applications : Squeeze 
100 spoiled lemons into a bucketful of broken pieces of 



634 HUNGARY LEATHER. 

alder bark, mixed with 10 lbs. of scraps of rusty iron 
and 1 lb. of bruised nutgalls. Stir up the contents of 
the bucket, and leave for fifteen days, at the end of which 
time the liquid is poured out and ready for use. Some- 
times the skins become mouldy before being colored if 
they are piled in a moist place ; and, in order to prevent 
this occurrence, prepare them in the following man- 
ner: — 

Wash them in the river, and, before being alumed, 
place them in a vat, and cover them with warm water, 
with which a bushel of bran and four ounces of ferment 
have been previously mixed, steep them three days in 
this bath, and alum them ; tread them out three times 
in warm water to remove the salt, and dry them. 

To give the skins a brown color, similar to that of 
tanned leather, steep them for a few days in tan liquor. 
If it is desired to blacken them, they may then, after 
receiving the four first dressings mentioned above, be 
brushed over twice on the hair side with a solution of 
copperas instead of the mixture prepared with lemon- 
juice. 



CHAPTER CLV. 

DEFECTS IN THE QUALITY OF HUNGAEY LEATHER. 

The causes of these defects have several different 
springs. Generally a bad skin will not make a good 
leather, whatever is the process. In the art of taiming 
we have indicated the signs to recognize a skin of bad 
quality, and the cuts made by butchers are the greatest 
trouble in the preparation of this kind of leather. 

We have said before that horse-hides must be used 



USES OF HUNGARY LEATHER. 635 

immediately after the animal has been killed; and this 
precaution must not be neglected, for if the skins expe- 
rience a beginning of fermentation the hair side loses its 
consistency. 

Leather imperfectly tramped during the aluming pro- 
cess, or which has been treated only with two or three 
waters, cannot be properly worked upon the platforms. 
It will not absorb as much tallow as is necessary, and is 
apt to contain horny and hard portions, which diminish 
its strength. The hides, which have spots of extrava- 
sated blood upon their surfaces, should be rejected as 
being weak and of bad quality. 



CHAPTER CLVI. 

USES OF HUNGARY LEATHER. 

This leather is particularly used by collar and harness- 
makers, who employ it for harness and main braces of 
coaches. For the latter, according to Dessables, they 
take the strongest leather and put five or six strips one 
on the other. After being sewed together, they are 
covered with curried cow-hide. Hungarian leather is the 
only one to which, in France, suppleness is given by 
tallow, but in some parts of Italy they tallow leathers 
even destined for soles. 

The tallowing is the most difficult operation. Too 
much heat renders the leather brittle ; not enough, it does 
not absorb the tallow well. If the tallow is too hot, it 
burns the leather ; if not, it does not penetrate. The diffi- 
culty is to operate at the right time. 

The tallowing is very important, for if it has not suc- 
ceeded, it cannot be done over, for the tallow will not 
penetrate well, and the leather takes a blackish color. 



636 HUNGARY LEATHER. 



CHAPTER CLVII. 

IMPROVEMENT OF M. CUEANDEAU.' 

CuRANDEAU, believing that the change experienced by 
the skins in the bath of alum and salt is due chiefly to 
the excess of sulphuric acid, proposed the substitution of 
this acid for alum. Consequently he prepares the fol- 
lowing bath : — 

Water 25 gallons 

Salt . . . . . . . . 20 pounds 

to which he adds 

Sulphuric acid . . . . . . 4 lbs. 

The skins, q,fter passing through the preliminary pro- 
cesses, are macerated in this bath, and after a maceration 
of twenty-four hours they are withdrawn and dried. 
As much progress is made by the skins in this bath in 
twenty- four hours as by those which are exposed for a 
much longer time in the bath previously given, and 
they possess all the best qualities of Hungary leather. 

The advantages of this process are the following : — 

1. It requires only two parts of acid, the price of which 
is lower than alum. 

2. This bath does not require to be as warm as alum. 

3. The manipulations are much shorter than by the 
use of the salt bath. 

* Memoire de I'Acad^mie des Sciences. 



PART T. 

GUT DRESSING. 

The art of the gut dresser consists in separating the 
middling or muscular coat of the intestines of certain 
animals from its external or peritoneal covering, and 
from its internal lining or mucous membrane, and may 
be divided into two distinct branches : the preparation 
of the intestine of oxen and cows for the preparation of 
alimentary substances, and that of the intestines of sheep 
for the manufacture of cords for various purposes. 



SECTION XIII. 

PREPARATION OF THE INTESTINES OF 

CATTLE. 

The intestines are submitted to the eleven following 
operations, which will be described in the order as be- 
low : — 

1. Scouring. 7. Desiccation. 

2. Turning over. 8. Disinsufflation. 

3. Putrid fermentation. 9. Measuring. 

4. Scraping. 10. Sulphuration. 

5. Washing. 11. Folding. 

6. Insufflation. 



638 GUT DRESSING. 



. CHA PTER CLVIII. 

OPEEATIONS FOLLOWED IN THE PREPARATION OP 

INTESTINES OF CATTLE. 

Description of the Worhsliop. 

The workshop of the gut dresser consists of a room 
twenty feet long, sixteen feet wide, and twelve feet high, 
with four windows ; these windows are opened or shut 
according to the seasons. Around the sides of the room 
are ranged casks of about sixty gallons capacity, and in 
the middle of the ground are fixed wooden stakes for 
attaching hooks. The remnants of the intestines are 
usually allowed to lie about the floor, and they exhale 
an odor which, with that from the putrefying intestines 
in the tubs, is the most disgusting that can be conceived, 
and is so permanent that the clothes of the workmen 
remain for a long time impregnated with it. Usually a 
well is sunk in a yard attached to the building for 
receiving the waste matters of the factory. 

I. Operation. — Scouring. 
As soon as the small intestines of oxen and cows are 
brought from the slaughter-house to the workshop they 
are steeped in water, in order to moisten and smooth the 
surfaces, so that the knife may slide easily over them. 
When this is done, an end of one of the intestines is 
attached, by tying it in a kind of knot around a hook, to 
one of the stakes in the centre of the room at a height of 
six or seven feet above the ground. The workman then 
grasps the depending portion between the thumb and 
first finger of the left hand, and gradually slides the 



PREPARATION OF INTESTINES OF CATTLE. 639 

hand down along the whole length of the intestine, fol- 
lows its motion by passing a knife, held in the right hand, 
over the surface, so as to separate the fat and as much 
as possible of the outer or peritoneal coat. 

Another portion of gut is then treated in the same 
way, and the operation is continued until all the con- 
tents of the casks have been cleaned. 

If any parts of the intestines have been scratched or 
divided by the butchers in separating the fat, these are 
cut off and thrown aside. 

The fat falling to the ground is separated from the 
feculent and other matters, and, after being washed a 
number of times, is dried, melted, and rendered. 

II. Operation. — Turning Over. 

The intestines are next washed in a large cask half 
full of water, and the workman proceeds to turn them 
inside out, by introducing a thumb into the interior of 
each, and working the gut upon it with the fingers until 
the whole is inverted. 

A number of the pieces are then tied together at their 
ends with a cord which is attached to the edge of the 
cask, and when a sufficient number of inverted intestines 
are thus fastened, they are left with only their original 
contents of water to undergo the next operation. 

III. Operation. — Putrid Fermentation. 

Experience alone can guide the workman in deter- 
mining when putrefaction is sufificiently^established. It 
should be carried only far enough to disorganize the 
mucous membrane and other parts which are to be 
separated from the middle coat of the intestines, and, if 
allowed to advance too far, the whole tissue will be 
softened and rendered useless. 



640 GUT DRESSING. 

In summer, two or three days of exposure are suffi- 
cient, and it requires from five to eight in winter. The 
putrefaction is known to have reached the proper stage 
when bubbles of gas begin to escape from the surface of 
the intestines. This operation is a most disgusting 
one, but it does not seem to be injurious to the health of 
those working in the room. 

IV. Operation. — Scraping. 

When sufficiently rolled, the pieces are untied, soaked 
in a cask half full of water, and the next operation con- 
sists in separating the disorganized mucous lining, which 
is now upon the outside. This the workman proceeds 
to effect by scraping it off with his thumb-nails until it 
is entirely detached. The operation is facilitated by 
frequently dipping the pieces in water. 

Y. Operation. — Washing. 

The intestines are introduced into tubs full of pure 
water, and they are stirred several times every day. 
The water is changed two or three times a day, and the 
operation is continued until the water comes from them 
unclouded and free from taint. 

VI. Operation. — Insufflation. 

When the intestines are perfectly cleaned, one end of 
each piece is tied with a string, and the workman intro- 
duces into the other orifice a hollow cylinder of cane, 
angle, or reed, ^out five inches long, and after making 
the joint air-tight by pressing the rim of the gut tightly 
around it, applies his mouth to the end, and expands the 
gut by blowing into it, and then closes the orifice, tying 
it tightly with a cord. If holes are found, the intestine 
is cut off at the place where they occur, and tied again 
with a cord. 



PREPARATION OF INTESTINES OF CATTLE. 641 



VII. Operation. — Desiccation. 
When all the pieces are thus filled with air, they are 
carried to the drying place, and are laid out, so as not to 
be in contact with each other, upon horizontal poles 
placed about five feet from the ground, and left until 
dried. 

VIII. Operation. — Disinsufflation. 

When perfectly dry, the pieces are taken down, cut 
across with scissors as near the ligatures as possible, then 
they are pressed and flattened with the hand so as to 
expel all the air contained in them. 

IX. Operation. — Measuring. 

They are then assorted into dijBferent sizes, according 
to the purpose for which they are intended ; they are 
collected into bundles and hung in a damp place prepara- 
tory to be sulphuretted. 

X. Operation. — SuIjpJiuration. 

After being kept in a damp place for some time, the 
intestines are exposed to the vapors of sulphur in a room 
five feet square and Qh feet high. For this purpose they 
are strung on sticks, and if not sufficiently moist when 
introduced into it, they are sprinkled over with water 
from a brush, and are then suspended across the upper 
part of the chamber to the number of a hundred bundles. 
A pound or more of flowers of sulphur is then put in an 
earthen dish on the floor of the room, and ignited by 
burning coals thrown upon it. The door is immediately 
closed, and the further precaution to prevent the escape 
of vapors being taken of luting it around the edges, and 
41 



642 GUT DRESSING. 

of gluing stout pieces of paper upon any apertures which 
exist in the room. 

XI. Operation.— jFbZc?*?i^. 

At the end of some hours, open the door of the room 
and allow the vapors to escape. The intestines which 
have been thus exposed are bleached, deprived of their 
bad odor, and are protected against the attacks of insects. 

While still damp they are twisted into hanks, packed 
'with camphor and sent to market. 



CHAPTER CLIX. 

DISINFECTION OF THE WORK-SHOPS. MODE OF 
SUPPRESSING PUTREFACTION. 

In order to prevent the offensive smell arising from 
the putrefaction of intestines, the following process of 
separating the mucous membrane has been devised by 
Labarraque. 

*The small intestines of fifty cattle which have been 
cleaned and turned inside out are mixed in a cask with 
two pailfuls of water, each containing li lb. of chloride 
of potash at 12 or 13°, and if there is not enough liquid 
to cover them, another pailful of fresh water is added. 

The whole is stirred about, well mixed, and left over 
night. The membrane can be detached as easily the 
next day, as after many days of putrefaction in the usual 
method, and the unpleasant odor is entirely avoided. 

The succeeding operations are performed in the same 
manner. 



GOLDBEATERS* SKIN. 643 



CHAPTER CLX. 

GOLD-BEATER'S SKIN. 

4 

This skin is prepared from the external or peritoneal 
coat of the caBcum or blind gut of neat cattle. The 
workman separates and turns over the portion which 
encircles the junction of this pouch with the rest of the 
intestines, and draws it off inverted from the other coats 
to the length of 25 or 30 inches. It is then immersed 
a short time in a weak solution of potash, and is cleaned 
by scraping upon a board with a knife. When thus 
well cleaned, and by soaking in water, the piece is 
stretched upon a kind of frame from 40 to 50 inches in 
length and 11 inches wide, and made of two uprights 
held together by two cross-pieces having longitudinal 
grooves, two and a half lines in width. The surface of 
the membrane, which was outside in the animal, is placed 
in contact with the upper part of the frame ; it is 
stretched in every direction, and is glued to its rim. 
Another membrane is then stretched above the first 
with its external surface placed upwards and is attached 
to it by gluing around the edges. When dry, the mem- 
branes are separated by running a sharp knife along the 
grooves. Each strip is then glued upon a frame similar 
to the first one, but without a groove, and is washed 
over with a solution composed of — 

Alum, 1 ounce. 
Water, 2 quarts. 

When the surface is dried, pass over it a sponge dipped 
in a concentrated solution of fish-glue in white wine, 



644 GUT DRESSING. 

rendered aromatic by cloves, nutmegs, or .camphor. 
When this coating is dried, cover it with a coat of white 
of eggs, and the strip is cut into pieces 51 inches square, 
which are then smoothed out under a press, and made 
up into leaves. 



CHAPTEE CLXI. 

LATHE-CORDS. 

These cords are made of intestines of horses, cleaned 
and prepared by the separation of the mucous membrane 
in the manner before described. A wooden ball, armed 
in its lower part with four cutting blades, at equal dis- 
tances from each other, is fixed by an upright piece of 
wood to a bench. The end of an intestine is then drawn 
over this ball, and as the gut is pulled downwards it is 
divided into four equal bands or strips. 

Four or eight of these strips, according to the thick- 
ness which it is intended to give to the cord, are tied 
with a peculiar knot to one end of a thick piece of cord. 
The end is passed around a peg introduced into a hole 
in a solid post, to the side of which a number of pegs are 
attached. At a distance of ten or eleven yards from 
the first one, another post is fixed, similarly provided 
with pegs, and over one of these latter the middle of the 
assemblage of strips is passed, the other end being 
brought back, and attached to the first peg by means of 
another knotted cord. The tied ends of the strips are 
then attached to the wheel by a hook connected with 
the whirl, which is made to revolve until the strips are 
sufficiently twisted. The twisted end is then kept 
stretched by attaching it to the peg, and any projecting 



CORDS FROM THE INTESTINES OF SHEEP. 645 

filaments are cut oflf. After being stretched for some 
time, the cords are then twisted again, and a third and 
a fourth time are twisted by hand, being each time 
rubbed with and drawn through a bunch of moistened 
horse-hair after the twisting, and again stretched out 
between the two posts. If the cord is not smooth and 
even after the twisting is completed, it is made so by 
rubbing with a piece of dog-skin. It is then dried, and 
by some makers is exposed to the vapors of sulphur. 
At last the ends are cut off, and the cord is rolled in a 
coil. 

In order to avoid the putrid emanations from the in- 
testines, which are generally in an incipient state of de- 
composition, Labarraque recommends to clean them at 
once ; turn the inside out, and put to soak over night 
in a cask containing, for fifteen or twenty intestines — 

Chloride of potash at 13 or 18°, 1 lb. 
Water, 4 galls. 

The mucous membrane is ready to be detached the 
next day ; and after its removal, and a thorough wash- 
ing, the intestines can at once be prepared as has been 
already described. 



CHAPTER CLXII. 

MANUFACTUEE OF CORDS FROM THE INTESTINES OF 

SHEEP. 

Eemove the intestines from the body of the animal 
when warm, clean and free them from fecal matter, and 
carry them to the workshop. If they are not perfectly 
clean, and if decomposition has been allowed to com- 
mence, they are stained so as to be unfit for most of the 
purposes for which they are intended. 



646 GUT DRESSING. 

They are unravelled and deprived of adhering fat 
while soaking in a tub of water; then they are placed 
in fresh water, and the small ends of the intestines are 
tied together, and laid on the edges of the tub, while their 
bodies are left to steep for two or three days in water 
which is frequently changed. The removal of the mucous 
and peritoneal coats is facilitated. After this, the intes- 
tines are placed upon a bench, which slopes down towards 
the edge of the tub, and the surface is scraped with the 
back of a knife blade in order to separate and remove the 
external membranes, in breadth of about half of the cir- 
cumference. The filandre (the coating) can only be 
freely removed in pieces of the proper size and length by 
pulling it off in the direction from the small to the large 
end of the intestine. It is employed as thread to sew * 
intestines, and to make the cords of rackets and battle- 
dores. In the event of its breaking, the separated pieces 
must be tied together, and they are laid aside with the 
others for use. 

The guts are then soaked in fresh water for twenty- 
four hours, and are taken out and scraped clean upon 
the bench with the back of a round-bladed knife. About 
eight feet of the larger ends are now cut off and sold to 
the sausage makers. The rest are then cut of a proper 
length, and are imbedded, as it were, between layers of 
salt. Alternating heaps of intestines and layers of salt 
are packed in until all the intestines have been salted. 
Some days after, remove and pack them with a small 
quantity of salt, so as to be ready at any time for the 
following process. 

After the curing process is completed, take out the 
intestines, and soak them over night in fresh water, and 
deposit them the following day in a lye made with — 

Pearlash ..... 8 ounces 

Water . . . . . . 4 galls. 



DIFFERENT CORDS. 647 

The strength of the lye is determined by the experience 
of the workman. Pour the lye in successive quantities 
upon the intestines, and pour it off again every two or 
three hours until they have been sufficiently acted upon. 
Then draw them two or three times through an open 
brass thimble, and press against it with the nail in order 
to scrape off unnecessary and projecting parts from the 
surfaces, after which they are selected for different pur- 
poses according to their size. 



CHAPTER CLXIII. 

DIFFERENT CORDS. 

Cords for Rackets. 

These cords are generally made of intestines of infe- 
rior quality, or which have been stained by commencing 
putrefaction. The pieces, while still moist, are sewed 
together with strips of the outer membranes or filandre, 
each junction being cut aslant so as to make it smooth 
and strong. 

Three or four of these intestines are thus attached by 
strings to the whirl, and are twisted in the usual way; 
after which the cord is smoothed and deprived of mois- 
ture by the hand of the workman, and is left stretched 
for a time. It is again twisted and rubbed with a bunch 
of horse-hair. The inferior kinds of cords are made by 
twisting one gut along with two or three pieces of the 
filandre. 

Whipcords are made of intestines of good quality, 
prepared, cut, and sewed as described. Each end is 
twisted separately, as whip-cords are seldom made of two 
intestines sewed together. Sulphur the cord once or 



648 GUT DRESSING. 

twice, and dye it black with common ink, or of a rose 
color with red ink, which the sulphurous acid turns to 
a pink color, or with a green dye. Dry and smooth the 
cords, and coil them up into suitable sizes for sale. 

Hatter^ s Gmds for Bowstrings. 

These cords are usually from sixteen to twenty-eight 
feet long; they are made by twisting the longest and 
largest intestines of sheep, four, six, eight, ten, twelve 
being put together according to the intended size. 

Their preparation requires more care than that of those 
which have been described before, and it must be per- 
fectly free from seams and knots. Twist them with the 
wheel in the usual way, and stretch them well and 
smooth them after each operation. When partially dried 
expose them twice to the vapors of burning sulphur, 
then rub them well with a bunch of horse-hair rope 
dipped in potash lye; dry them while in a state of ten- 
sion, cut off, and coil. 

Clock-Maher^s Cord. 

This kind differs from the other in being extremely 
thin. It is made of intestines of the smallest size, or of 
stripes made by dividing each gut into two pieces by 
drawing it down over a kind of lancet mounted upon a 
leaden or wooden ball, which guides the blade, the two 
sections of the gut falling into a vessel placed beneath. 
Sometimes clock-makers use cords of larger diameter 
made of two or more intestines. 



CORDS FOR MUSICAL INSTRUMENT STRINGS. 649 



CHAPTER CLXTV. 

CORDS FOR MUSICAL INSTRUMENT STRINGS. 

These strings should be of uniform diameter, perfectly 
smooth, round, and free from shreds and filaments. 
They should be as little liable as possible to stretch or 
break, and should preserve their polish and transparency 
during all the changes of weather. Their manufacture 
requires great experience and dexterity. The best 
strings have been made from time immemorial in Italy, 
and although some of superior quality are manufactured 
in France, the preparation of treble strings is confined 
to Naples. The membranes of lean animals are well 
known to be much more tough than those of animals in 
high condition, and the superior quality of the strings 
made at Naples is attributed in a measure to the small- 
ness and leanness of the sheep in its vicinity. 

The guts intended for these strings are first very care- 
fully scraped. Then dissolve in six pailfuls of water 
three pounds of potash, and mix with the same quantity 
of water five pounds of pearlash, clarify the solution by 
adding to it a little alum. Keep the two solutions in 
stoneware vessels. Then half fill stoneware pans with the 
intestines, and pour in the potash liquor, mixed with an 
equal quantity of water, until the vessels are full. 

Steep the intestines three or four days, and even 
longer, changing the solutions twice daily, and making 
them progressively stronger by adding each time some 
of the ash lye and diminishing the quantity of water 
mixed with it. Each time that the solution is changed, 



650 GUT DRESSING. 

the intestines are removed from the vessel and are re- 
placed, after draining upon a sloping table, and after 
being passed through a thimble in the manner before 
described. The effect of the alkaline solution is to 
bleach and swell the intestines, and they must be 
removed from it at the first appearance of little bubbles 
of gas escaping from them, or they will be rendered unfit 
for use. This occurs oftener in summer than in winter. 
After being passed through the thimble so as to smooth 
and equalize their surface, and washed in fresh water, 
the intestines are attached to the frame in order to be 
twisted. This frame is five feet three inches long and 
twenty-five inches broad. A number of pegs are fixed 
in one of its sides, and a double number of holes are 
bored through the other side, so that the cords passed 
through them are kept in place when pegs are intro- 
duced. The ends of the intestines are first placed to- 
gether upon the edge of the tub in which they have been 
soaked, and two or three or more of the same diameter 
and length are selected and fixed to one of the double 
holes by means of a peg, and the bodies of the intestines 
are then drawn out exactly of the same length and 
brought over the corresponding large pegs on the opposite 
side of the frame, the ends being carried back and fixed 
in the other one of the two holes. If some of the in- 
testines are not sufiiciently long to stretch across, they 
are sewed to other pieces as near as possible to the end 
of the cord, so that the points may be near the extremity 
of the string, and may not interfere with the uniformity 
of surface of its main part. The intestines are then 
twisted on the hooked wheel in the ordinary manner, 
and are exposed for two or three hours in the sulphuring 
room, after which they are forcibly rubbed with the 
horse-hair rope and twisted and rubbed again. They are 



CORDS FOR MUSICAL INSTRUMENT STRINGS. 651 

again exposed to the vapor of burning sulphur, twisted 
once more and sulphuretted for a third time, after which 
they are left to dry in a state of tension. 

The strings are known to be sufficiently dried when 
one of the strands, upon being removed from its peg, 
shows no tendency to turn, but remains in the straight 
position in which it is held. When the strings have 
arrived at this degree, they are rubbed over with olive 
oil, cut off at the ends, and coiled up. 

The fourth strings of violins, which are wrapped in 
wire, are neither sulphuretted nor oiled. The string in- 
tended to be wrapped is cut off the length of one and a 
quarter yards, and one of its ends is attached to the hook 
of the wheel, and the other to the ring of a whirl, which 
keeps the string stretched by means of a weight at the 
end of a cord fastened to it and passing over a pulley. 
The wire is then fastened around the string close to the 
whirl, and as the wheel is made to revolve, the string 
and the whirl turn with it. The workman supports the 
string with his left hand, and the wire passing through 
his right hand is made to revolve around it in close spiral 
turns until it is entirely and equally covered. 

As has been before observed, the utmost care and skill, 
on the part of. the workman, are required for the manu- 
facture of harp or violin strings of good quality. His 
experience alone will enable the workman to conduct the 
diflferent operations with the requisite dexterity. 



PAET VI. 

DIFFERENT KINDS OF APPARATUS USED 
BY LEATHER MANUFACTURERS. 



CHAPTER CLXV. 



IMPROVED MACHINE FOR ROLLING GREEN OR WET 

LEATHER* 

Mr. J. Whitney, of Winchester, Mass., has invented 
a new and useful improvement in machinery for treating 
green or wet leather, so as to express the water or tan- 
ning liquor from the same, and not discolor the surface 
thereof. The following is an explanation of his patented 
machinery. 



Fig. 161. 




' Fig. 161 is a plan with a portion of the frame and 
rollers broken away at the centre to show the treadle. 

* Patented by J. Whitney, of Winchester, Mass., March 24, 1863. 



654 APPARATUS USED BY LEATHER MANUFACTURERS. 

Fig. 162 is a vertical longitudinal section through the 
centre of the rollers, showing an arrangement of levers 
for relieving the pressure. 

Fig. 162. 




Fig. 163, an end elevation of the machine. 
Fig. 163. 




IMPROVED MACHINE FOR ROLLING LEATHER. 
Fig. 164. 



655 




Fig. 164 is a modification of the lever arrangement. 

Figs. 165, 166, 167, 168, 169, 170 are details of the 
machine. Similar letters of reference in the figures in- 
dicate corresponding parts. 

In the process of tanning skins of which thick leather 
is made, it is necessary to split the leather in order to 
reduce the thickness; and in order to accomplish the 



Fig. 165. 



Fig. 166. 





Fig. 167. 



Fig. 168. 





656 APPARATUS USED BY LEATHER MANUFACTURERS. 
Fig. 169. Fig. ITO. 





splitting at certain stages of the tanning process, the tan- 
ning liquor or water must be expressed from it before 
commencing the splitting operation, and in the express- 
ing operation, means such as will not discolor the surface 
of the leather must be employed because the market 
value is greatly affected by the color. 

If iron rollers are used, the tannic acid causes a cor- 
rosion of the metal and the rust is imparted to the surface 
of the leather, and besides this the leather is but imper- 
fectly operated upon, as the surface of the rollers cannot 
conform to the irregularity of thickness of the leather, 
nor is it desirable at this stage of the tanning process to 
so compress the leather as to close its pores, therefore it 
is impracticable to overcome the irregularity in thickness 
by making the leather conform to the rollers. The 
latter diJSiculty obtains with all other hard surfaced 
rollers, even though the discoloring of the leather from 
corrosion might not be experienced. 

Many machines have been devised for splitting and 
rolling leather at one operation. But this process of 
Mr. Whitney's is especially designed for the use of the 
tanner ; and the only office it is intended to perform is 



IMPROVED MACHINE FOR ROLLING LEATHER. 657 

that of expressing the tanning liquor or water from the 
leather in order to prepare it for the action of such ma- 
chines as have been devised for splitting leather. 

A A is a frame constructed in a suitable manner to 
receive the component parts of the machine. B B are 
two rollers of equal size, placed one above another, and, 
with their journals C C, revolving in boxes D D and E. 
The revolution of the rollers is effected by means of gears 
F, G, H, I, which are arranged so as to allow the rollers 
to be set at any required distance apart without break- 
ing the gearing connection as shown. 

A gear F is fixed to the upper roller, and a corres- 
ponding gear to the lower roller outside of the journals ; 
these gears F and I are both of the same size, and their 
diameter being less than the diameter of the rollers, the 
teeth of one never come in contact with the teeth of the 
other. The intermediate gears G and H are both of a 
size, but a little larger than the roller gears F and I ; 
they are placed back of the roller gears, and fitted to 
revolve on studs J, J, attached to the frame. The lower 
intermediate gear H meshes into and drives the roller 
gear I ; it also meshes into and drives the upper inter- 
mediate gear G, and the upper intermediate gear G 
meshes into and drives the upper roller gear E. 

Motion is given to the rollers through the gears by a 
driving wheel K, with a pinion L attached thereto, which 
meshes into and drives the lower intermediate gear H ; 
the pinion L is made fast to the driving wheel K, and is 
fitted to revolve on a stud M, set in the frame below the 
lower intermediate gear H. The roller boxes, D D and 
E E, have a tongue at each end, as represented in Figs. 
165, 166, 167, 168, and are made to slide up and down in 
grooves N N, formed in the frame A A. At each end 
of the upper roller, directly over the journals C C, there 
42 



658 APPARATUS USED BY LEATHER MANUFACTURERS. 

is a gear screw a, hung to the cap piece of the frame, 
and made to revolve in holes formed therein, and fitted 
to screw in the upper roller box D, for the purpose of 
elevating or depressing the upper roller. These screws 
a, a stand in a vertical position, and have a collar above 
and below the cap piece 0, to prevent them from sliding 
up or down, and each screw has a fixed level gear h on 
the upper end above the cap piece 0. A horizontal 
shaft c is placed above the cap piece 0, running length- 
ways of the machine, and fitted to revolve in boxes d d 
on the cap piece 0, with a fixed level wheel e e on each, 
and corresponding with those of the screws, and fitted 
to mesh therein. On one end of this shaft c, outside of 
the level gear, there is a fixed hand-wheel /, by which 
the shaft may be turned at pleasure. A rubber spring 
g, or its equivalent, is confined in a box h, and placed 
directly under each of the lower roller boxes E E, of 
sufficient power to give the required pressure. Over 
each rubber spring g there is an oil protecting cap i, on 
which the roller boxes E E rest. This cap i projects 
down on all sides outside of the box n, and is fitted to 
slide freely up and down thereon, and made to cover 
the spring g, and keep the oil used in lubricating the 
journals from coming in contact with it ; the cap i also 
has a stirrup y attached to it, as represented in Figs. 169 
and 170. There are two horizontal levers h, Tc, one at 
each end of the machine, extending longitudinally directly 
under the centre of the roller B. Each of these levers 
k extend through and rest on the stirrup y, and are hung 
at the outer end of the pins 1 1 for their fulcra outside 
of the frames. There are two connecting links wi, ???, 
one attached to the inner end of each lever k, by a pin 
ti, and extending downwards ; both of them are connected 
by a pin o, to a horizontal treadle^, running transversely 



IMPROVED MACHINE FOR ROLLING LEATHER. 659 

through the lower part of the machine at the centre of 
its length. The treadle p is hung at its rear, and on a 
pin g, in the back part of the frame and the forward, 
and* extends out beyond the front of the frame, so as to 
give a convenient chance to place the foot upon it. Thus 
it will be readily seen that by giving a gentle downward 
pressure with the foot on the treadle, the combined 
action of the levers k, k^ on the stirrups j,/, will cause a 
depression of the oil protecting caps i, i, together with 
the lower roller B. 

When the pressure on the rollers is not given by the 
use of springs, this combination of levers may be applied 
to give the pressure by extending the stirrups up, and 
attaching them to the upper roller boxes D, D, and at- 
taching the geared screws a a to the lower boxes E E ; 
in that case the pressure would be given by the foot on 
the treadle. This combination of levers may also be 
used to give the pressure in another form, as represented 
in Fig. 164 ; the only change necessary to be made is to 
place the fulcra pins I, I, of the levers k, k, inside of the 
frame instead of outside, and stand an upright rod r. 
Fig. 164, on the outer end of each lever k, extending up 
centrally to the under side of the lower roller boxes E E. 
Thus, by giving a gentle downward pressure with the 
foot on the treadle p, the combined action of the 
levers k k will cause an upward pressure to the lower 
roller B ; in this case the geared screws would be at- 
tached to the upper roller boxes, as shown in Figs. 161 
and 162. 

Operation. 

Wet leather to be deprived of water or tanning liquor, 
is introduced between the two rollers after the same 
have been adjusted apart to the proper degree; this 



660 APPARATUS USED BY LEATHER MANUFACTURERS. 

adjustment being effected by depressing • the treadle or 
raising the upper roller with the geared screws. The 
leather having been introduced, the rollers are adjusted 
together by withdrawing the foot from the treadle *and 
lowering the boxes of the upper roller with the geared 
screws. Now by operating the gearing the rollers B 
have a uniform rotary motion imparted to them, and 
the leather is carried through under a pressure due to 
the rubber surfaces and to the geared screws and to the 
springs g g. This action upon the leather causes a 
thorough expression of the water or tanning liquor 
therefrom. The amount of the pressure is graduated 
by depressing the springs g, g, and operating the geared 
screws. It is obvious that the rubber surfaces of the 
rollers accommodate themselves to the irregular surface 
of the leather, and thus a uniform action is obtained. It 
is also obvious that the rubber surfaces protect the 
leather from discoloration as the tanning liquor cannot 
get to the iron of the rollers so as to cause a corrosion 
thereof. It is also obvious that the pores of the leather 
will not be closed by hardening or flattening down the 
leather, as the leather is between elastic surfaces. 



MACHINES FOR FINISHING LEATHER. 



661 



CHAPTER CLXVI. 

MACHINES FOR FINISHING LEATHER. 

S. P. Cobb, of South Danvers, Mass,, patented, in 1860, 
a machine for finishing leather, of which the following 
is a description. 

Fiff. 111. 




Fig. 171 is a side elevation. 



662 APPARATUS USED BY LEATHER MANUFACTURERS. 



Fig. 112. 




Fig. 172 is a front elevation. 

Fig. 173 is a transverse and central section of the 
machine. 

Fig. 174, rear view of the vibrator and parts at its 
foot. 

Fig. 175, top view of the bed cams, their connection 
and operating screws. 

In the drawings, A exhibits a table, from and above 
which a frame B extends and serves to support a 
vibrator or vibratory arm D and a fly-wheel E. This 
arm supports the sleeker or -finishing tool a, which in 



MACHINES FOR FINISHING LEATHER. 



663 



Fiff. n3. 




this machine is fastened to a tilting plate or frame &, 
which at its front edge is hinged to what is termed the 
carrier o. This carrier slides freely in a longitudinal 
direction within the vibrator D, and at or near its upper 
end is jointed to a forked connecting rod F, which strad- 
dles the vibrator, and is jointed to the front side thereof, as 
shown at d. Each joint pin e of the carrier c projects 
through a slod/made in the vibrator, as shown in figure 
171 ; the near end of the connecting rod being applied to, 
and so as to turn on a crank pin g extending from the 
side of the wheel. By revolving the wheel the vibrator 



664 APPARATUS USED BY LEATHER MANUFACTURERS. 
Fiff. lU. Fig. 175. Fig. 1T6. 




with the carrier and finishing tool will not only have an 
oscillating motion imparted to them, but the carrier c will 
be raised so as to lift thereon during the movement of the 
vibrator away from the fly-wheel, the tool being forced 
down upon the skin during the return movement of the 
vibrator. 



MACHINES FOR FINISHING LEATHER. 665 

Within the carrier c there is a short horizontal shaft 
h, which supports a sectoral lever i; this lever has its tail 
part jointed to a connecting rod k, whose lower hinder 
part hinges to the tilting plate or frame h. Further- 
more, the toothed section of the lever i engages with a 
spring click Z, carrying the angular tooth Z', and being 
supported by th^carrier c, the whole being arranged as 
shown in Figures 173, 174, 176, the latter being a trans- 
verse and vertical section of the vibrator D and the 
carrier c. The shaft h extends through a slat m (made 
in the vibrator) and has an arm or lever ti projecting 
from it, as shown in the drawing. By means of such an 
arm n, shaft A, sectoral lever i and click, the angular 
position of the tool, relatively to the upper surface of 
the bed, may be varied ; it being difficultj if not im- 
possible, however, to accomplish this, when the vibrator 
is in rapid motion. It has been applied to the vibrator 
and its tilting plate, a mechanism by which the tilting 
plate, while the vibrator may be in oscillation, may be 
moved in its fulcrum, so as to change the angle of the 
tool to the bed while the tool may be passing over any 
portion of a skin. As a skin will often be thicker in 
some parts than in others, it becomes desirable to have 
some means by which the pressure or action of the finish- 
ing tool may be equalized on the surface, and this while 
the said tool may be in movement. 

In order to accomplish this, apply to the vibrator a 
slider D to slide thereon. From this slider three pro- 
jections, p, q, r, extend, as shown in Figs. 171, 172. The 
lever n, before described, extends between the projections 
g, r, while the other projection p is extended into the 
slot S of a long lever I, whose fulcrum t is supported 
by the frame B. The said lever, near its opposite end, 
is pressed against the frame by a friction-plate u, held 



666 APPARATUS USED BY LEATHER MANUFACTURERS. 

in place by screws v v. By laying hold of the slatted 
lever, and forcing it either downward or upward, one of 
the pins q r will be made to so act on the lever or arm 
n as to move the same and steadily change the angular 
position of the tilting-plate or its tool relatively to the 
bed. 

Furthermore, the said bed, as in various other leather 
or morocco-finishing machines, plays vertically within 
the table A, and rests on the tops of two cams, K, L, 
which, in their turn, are respectively supported on two 
other cams M N. These latter cams are upheld by 
two vertical rods 0', 0', each cam turning freely on its 
rod, but being supported on a shoulder X, formed on 
the rod. The two rods play vertically within a frame 
P, which supports springs Y, Y, through which the rods 
respectively pass, and on which they are sustained by 
means of screw-nuts Z, Z, screwed on the rods, the whole 
being as shown in the drawings. In this way the bed 
C may be said to be supported on springs. 

The touching surfaces of the two cams K, M, or L, N, 
are helical in form. The two lower cams are connected 
on the same side each by a rod a\ whose ends, by means 
of joint-pins, are connected to projections or flanches 5', 
h', of the lower cams, the same being such as to enable 
the two cams to move or turn simultaneously in the 
same direction, while the rod a' may be moving length- 
wise. 

The other two cams are similarly connected by a 
rod c', but the rod extends from one side of one cam to 
the opposite side of the other. Screw rods d' (f are 
connected with the two rods a' d respectively, and 
screwed throughout a stationary plate /', and have 
cranks of h' on their outer ends, the whole being so 
that, by turning either crank, a longitudinal movement 



MACHINES FOR FINISHING LEATHER. 



667 



shall be imparted to the rod a' or (f, with which the 
screw-rod of the crank may be directly connected. By 
revolving one crank, a vertical movement of the bed will 
be produced. By revolving the other, the bed may be 
tipped as occasion may require. Thus, by means of the 
mechanism directly below the bed, the vertical adjust- 
ment of opposite ends of the bed may be varied so as 
to either raise or depress both ends equally at the same 
time, or unequally, as circumstances may require. 




668 APPARATUS USED BY LEATHER MANUFACTURERS. 

In 1863, Mr. S. P. Cobb invented and patented another 
machine for dicing, polishing, or finishing leather, a de- 
scription of which will, we think, interest our readers. 

Fig. 177 is a side elevation of the machine. 

Fig. 178 is a front elevation of the machine. 

Fiff. 178. 




Fig. 179 is a vertical section of the machine. 



MACHINES FOR FINISHING LEATHER. 



669 



Fig. 1T9. 




The nature of his invention consists as follows : — 
First, in a peculiar mechanism for obtaining the com- 
pound movement of the vibrator or dicing staff; also in 
the combination and arrangement of a brush or cleansing 
mechanism, with the dicer or finishing tool and its staff 
or vibrator ; also in the combination and arrangement of 
an adjustable smoothing tool with its dicer and its staff;, 
also in the combination and arrangement of a dicer 



670 APPARATUS USED BY LEATHER MANUFACTURERS. 

cleansing mechanism, with the dicer, its staff, and curved 
bed. 

In the drawings, A exhibits a table from and above 
which a frame B extends, and serves to support the ful- 
crum S of a rocker lever c, which is arranged as shown 
in the figures. The dicing staff or vibrator D is jointed to 
one arm of the said rocker lever, and at its lower end 
supports the sleeker dicer, or finishing tool a, which is 
fastened to a tilting plate or frame 6, hinged to the lower 
end of the vibrator or dicing staff D. A forked connect- 
ing rod straddles the vibrator, is jointed to it and to the 
crank pin of a fly-wheel E. Furthermore there is jointed 
to the connecting rod within its fork, and at a short dis- 
tance from the dicer staff, a pitman c, which extends up- 
wards, and at or near its upper end is jointed to the 
rocker lever c hereinbefore described, the arrangement 
of the said pitman with respect to the dicing staff and 
rocker lever being as shown in Figs. 177 and 179. On 
revolving the fly-wheel in the direction of the arrow {y) 
marked thereon, the dicer staff will not only be vibrat- 
ed with a pendulous motion, but while moving towards 
the fly-wheel, the said dicing staff will be moved or 
pressed downwards towards the bed, in a manner to keep 
the dicing or finishing tool in contact with a piece of 
leather when on the bed. So while moving away from 
the bed, the dicing staff will be raised upwards, so as to 
elevate the dicer or polishing tool entirely off and keep 
it out of contact with the leather. 

In advance of the polisher or dicing tool, there is 
arranged a brush H held by a suitable supporting frame 
d, having one or more springs e so arranged and applied 
to it and the dicer staff as to press the brush in a down- 
ward direction and upon the leather, while such leather 
may be resting on the bed G. This brush moves with 



MACHINES FOR FINISHING LEATHER. 671 

the dicer and its staff, and is for the purpose of removing 
from the surface of the leather, and in advance of the 
dicer, any dirt, grit, or any extraneous matter that may 
collect on the leather, and be likely to cause injury to 
its surface from the action of the dicer. There is also 
placed to the rear of the dicer a smoothing tool I, it 
being carried by a clamp /, attached to the dicer staff. 
A spring g suitably applied to the smoothing tool serves 
to depress it, as occasion may require. The object of 
the smoothing tool is to remove from the surface of the 
leather, ,while the machine may be at work, more or 
less of the graining made by the dicing tool, or in other 
words, to low down the graining as may be desirable. 
The said smoothing tool may also be employed irrespec- . 
tive of the dicing tool, and either one or both may be 
used as occasion may require ; a rod i, jointed to the tilt- 
ing plate h of the dicing tool, extends upwards along 
the dicer staff, the said rod at its upper end being jointed 
to the shorter arm of a lever k, whose fulcrum t is sup- 
ported by the dicer staff. This lever projects from the 
dicer staff, and has projecting from its longer arm a 
pin or stud which goes between the prongs of a forked 
lever m, formed and arranged as shown in the figures.. 
By laying hold of the longer arm of said forked lever, 
and moving the same, the dicer tilting frame may be 
either raised or lowered, as circumstances may require. 

At the front end of the curved bed G, there is arranged 
a dicer cleaning tool or scraper o, which is supported by 
a vibratory lever p, to which vibrating movements may 
be imparted by means of a foot lever q, and a connecting 
rod r. The same being arranged as shown in Figs. 177 and 
179 . By elevating the scraper previous to the expiration of 
any advance movement of the dicer, the said dicer in the 
continuation of its movement will be carried in contact 



672 APPARATUS USED BY LEATHER MANUFACTURERS. 

with the scraper in such manner as to be cleaned or 
scraped thereby. In this way the grease or dirt which 
may collect on the dicer or polishing tool may be re- 
moved therefrom. 

The advantages of this machine are the following : — 

1st. It is noiseless comparatively, and adapted to all 
the different kinds of work of all others combined with 
much more convenience. 

2d. The tools are carried in an oblique position, which 
may be varied so as to make a sharp or flat angle in 
relation to the bed, which is done by the rod i, i, encased 
in the pendulum and connected at or near b, to the tilt- 
ing plate ft, and operated by the long armed forked lever 
m m acting on the pin of the short lever at I, which is 
connected with the encased rod ^, ^, etc., all done while 
the machine is at work. 

3d. The bed may be adjusted (by means of the cams 
and rods) by the workman without leaving his place or 
stopping his work. 

4th. The tools may be cleaned from dirt or any, ex- 
traneous matters which may chance to stick to them 
while at work, without stopping the machine by means of 
a scraper at the back end of the bed and operated by the 
foot rod q and its connection at the front end. 

Any kind of tool may be used, either stone, glass, or 
steel. There is also an apparatus for pebbling, which 
can be attached at pleasure; and further, a brush which 
can be used in connection with the other tools, or with- 
out, and is nicely adapted to belt, cord leather, etc. 



LEATHER POLISHING MACHINE. 673 



CHAPTER CLXVII. 

LEATHER POLISHING MACHINE. 

The highly-finished surface of fine leather is usually 
imparted by hand labor. In the following we present a 
view of the machine for accomplishing this object, which 
does work in a superior manner, and effects a great sav- 
ing in time and labor. This machine was invented by 
Messrs. R. and C. Smith, of Stockport, New York. The 
construction and operation of this machine is as follows : 

The framing A carries a vertical shaft B, which works 
between two parallel bars C at the top, and is connected 
at Z) to a bar sliding between two rollers at E and F. 
This vertical shaft B is jointed to the connecting rod 0, 
which, in turn, is fixed to a cross-head sliding on guides 
between the timbers IT; from this cross-head proceeds 
the pitman / to the crank wheel /, which is turned by 
power of any kind, either steam, water, or by hand when 
neither of the other two is available; the bar B has a 
metallic roller K, fastened at its lowest extremity, so 
that it can be adjusted to suit the nature of the work, 
and the skin to be polished rests upon a metallic plate 
underneath it. At one side of the skin may be seen a 
clamp Z; the skin is attached to this, as shown, and 
the clamp is then fed over the surface of the table, 
the roller, which is the polisher, acting on it continually. 
The belt which drives the feed gear is seen at M. There 
is also an arrangement for raising the tool stock so that 
the operator can place another skin underneath the 
roller or tool when the first one is completed. This 
43 



674 APPARATUS USED BY LEATHER MANUFACTURERS. 



Fig. 180. 




arrangement consists in applying a lever at one side of 
the frame so that the workman can press upon it with 
his foot, and then accomplish the object. The frame 
slides through mortises Nat the bottom. The stroke of 
this machine may be altered at will by simply turning 



Perkins's machine for graining leather. 675 

the hand wheel 0. This wheel is on a shaft that runs 
through the main driving shaft, and the pinion P is 
secured to it. There is a rack Q, on one side of the 
crank, which elevates or depresses the pin when the 
pinion is turned ; suitable means are provided for keeping 
the pin stationary, except when it is necessary to move 
it. These are the principal parts. It is obvious that 
when the tool stock B is put in motion that the sliding 
action of the wheel Kvf'iW impart a high finish to the 
leather in a manner apparent to every one without any 
further explanations. These machines are said to work 
exceedingly well. Several of them have already been 
put in operation. 



CHAPTER CLXVIII. 

jacob pekkins's machine for pommelling and 
graining leather. 

Fig. 181, side view. 

Fig. ] 82, front view. 

Fig. 183, plan. 

a. Framework held together by bolts with nuts. 

h. Large horizontal wooden shaft, its iron pivot c turn- 
ing in the copper collars d. 

e. Four wooden arms radiating from the middle of the 
shaft &, and curved at their bases. 

/. Four fluted or grooved cylinders of lignum vitaB wood, 
in the ends of the wooden arms. The grooves are near 
or far from each other, according to the grain intended 
to be given to the leather. 



616 APPARATUS USED BY LEATHER MANUFACTURERS. 




f.E5 



Fig. 182. 

J' 

fin 



«.K 



%n. 



m 

7^ 




w 



fM 



g. Two iron grooves attached to each of the arms, and 
receiving the pivots of the cylinders / in their extremi- 
ties ; these grooves are kept in place by the guides ^, and 
slide against the blocks A, Fig. 181. 



Perkins's machine for graining leather. 677 

h, Fig. 181. Springs resting against the lower part of 
the base of the grooves g, and by their elasticity tending 
to push these grooves away from the shaft h. 

Fig. 183. 




I. Screw and nut, the end of which presses to the 
required extent upon the lower end of the groove g. 
When this screw is tightened, the groove presses down 
the spring, and approaches the shaft ; when loosened the 
opposite movement takes place. 

m. Pieces forming a support or frame, and curved in 
the form of arcs of the circle of which the shaft is the 
centre, so as to allow the arms to revolve freely. This 
frame should be very firm, and supplied with a surface 
of hard wood for the cylinders to rotate upon. 

n. Circle attached by bolts to the arms, and serving 
to strengthen them. 

o. Pulley upon the shaft h, intended to receive the 
motive power by means of a band. 



678 APPARATUS USED BY LEATHER MANUFACTURERS. 

The leather, when prepared in the ordinary way, and 
ready to be grained and polished, is placed upon the 
wooden table or frame m, and the shaft h is turned. 
The grooved cylinders /, stamp furrowed surfaces upon 
the leather, and owing to the resiliency of .the springs, 
adapt themselves to its variations of surface and thick- 
ness. The skin is moved about by the workman so that 
the different portions shall all be grained in the required 
directions, and during the process', the surface of hard 
wood m is from time to time moistened with water or oil, 
to prevent it from becoming heated. 

The cylinders/, in the course of their revolution, press 
against brushes which keep them clean. Upon each of 
their axles is a ratchet-wheel with a catch jp. Fig. 181, 
the object of which is to prevent them from revolving. 
When the grooves of the cylinder are worn out at one 
point, they can be renewed by turning the cylinder round, 
so as to present a new part of its circumference. 

The shaft, the pulley, the arms, and the circular sup- 
port can all be made of cast-iron in one piece. 



CHAPTER CLXIX. 

NISBET'S GROUNDING AND PUMICING MACHINE. 

Mr. John Nisbet, of England, recommends the substi- 
tution of machinery for the hand in the laborious pro- 
cess of grounding, or frizing, and has invented for that 
purpose a very ingeniously constructed apparatus. He 
employs knives and pumice stones, or other sufficiently 
rough materials, set into revolving cylinders which are 
made to turn in contact with the surfaces of leather. 
Fig. 184 represents a side view; and Fig. 185 a longitu- 



NISBET S GRINDING AND PUMICING MACHINE. 



679 



dinal section of one of these machines ; a a, framework, 
6, axle turning in the supports c c, and made to revolve 



Fiff. 184. 



FiV. 185. 





by means of a strap around the pulley d\ e e, series of 
cross-pieces, or arms, each of which is provided with a 
paring-knife /, which, by the revolution of the shaft, is 
brought in contact with and made to pare the surface of 
the skin or portion of skin placed on the mattress g. 
This mattress is stuffed with hay or other suitable mate- 
rial, and is covered with oiled leather. It is placed upon 
the top or table of a car mounted on four grooved wheels 
li h, which run on the railroad i i. 

The arms which carry the knives are made to revolve 
at least 360 times in a minute, and the rapidity of mo- 
tion can be increased if it is desirable to do so. 

The workman places the skin, or portion of skin, upon 
the mattress, and pushes the car forwards, so that the 
end of the piece shall be under one of the series of blades. 
These latter, by their revolution, then draw the leather 
away from the workman, and pare its surface while he 
retains the extremity in his hands and retards its pro- 
gress more or less, according to the amount of action to 
which it is desired to expose it. When one side is thus 
pared throughout, the band is slipped off from the pul- 
ley, so as to stop the revolution of the axle ; the car is 
drawn back, the leather turned, and the strap being re- 
placed, the other side is made to undergo the same treat- 



680 APPARATUS USED BY LEATHER MANUFACTURERS. 



ment. Besides great rapidity, this operation secures a 
uniform paring of the leather. 

When light and thin skins are treated in this manner, 

• Fig. 186. 




^ 



(T-'Bi 



the intervals between the knives are filled up with 
wooden blocks, or wedges, so that the axle is surrounded 
by a compact cylinder of wood, beyond which the knives 
project only to a slight extent. Fig. 186 shows the 
plan, and Fig. 187 the side view of the machine so modi- 
Fig. 18T. 




l)-iJtuciii-:^= 



_.g_ 



fied ; and Figs. 188, 189, 190, and 191, exhibit a front 
view of the arms and knives from between which the 

Fig. 188. Fig. 189. Fig. 190. Fig. 191. 





wooden wedges have been removed ; a section ; a side 
view ; and front view of the series of knives /, and of 
the wedges/. 



nisbet's grinding and pumicing machine. 681 



Figs. 186 and 187 also represent the apparatus for 
jpumicing leather. The pumice stones h, or other suita- 
ble rough substances, are attached to the shafts m, which 
are made to revolve by the ordina^;^ means. In other 
respects, the machine resembles the preceding one, the 
same letters indicating corresponding parts of both. 

The leather submitted to the action of this niachine, 
is first pared by means of two sets of knives/, which 
are represented in the figure as turning upon two shafts, 
and it then passes under the pumicing cylinders, which 



Fig. 192. 



6 



Fig. 193. 



Fig. 194. 

e 



act progressively upon every part of the surface. Figs. 
192, 193, and 194 exhibit, the first section, the second 

Fig. 195. 



<D 



o^ 



a side view, and the third, a front view of these cylin 
ders and stones. 



Figures 195 and 196 show, the one a 




cross section, and the other a longitudinal section of the 
pumicing machine while in action. 



682 APPARATUS USED BY LEATHER MANUFACTURERS. 



CHAPTER CLXX. 

EMBOSSING OF LEATHER. 

This is a method of manufacturing ornamental leather 
intended for furniture, hangings, bookbinding, and other 
uses. 

Bernheim and fjahouriavJs Process. 

The plates, by means of which the figures in relief 
are stamped upon the leather, in this process, are made 
of type-metal, or fusible alloy, cast in plaster moulds, 
on which the reverse of the figures has been designed. 
The type-metal plates are used for stamping leather 
without the assistance of a press, by which they would 
be broken to pieces, and those of fusible alloy are em- 
ployed for large single designs in panel upon hangings, 
or for the repetition of the same figures, by associating 
a number of plates together. For this latter purpose, 
as many plates as are necessary for the whole design are 
placed together upon a level surface, in their proper 
j)laces, and their edges are then joined together, first by 
running a hot iron along them, and then by filling up 
the interstices with melted fusible metal. The project- 
ing veins of metal are then cut and scraped off, and the 
whole presents the appearance of a single plate. 

The large plates thus, prepared will not bear the force 
of a press, but are used with the assistance of heat. The 
ingredients of which the alloy is composed are not in 
the proportion to make the most fusible metal, the quan- 
tity of lead being somewhat greater than in the ordinary 



BERNHEIM AND LABOURlAu'S PROCESS. 683 

alloy. Those plates which are intended to be subjected 
to the action of the press, also, have a smaller quantity 
of tin in their composition than is usual, so as not to be 
rendered brittle by an excess of it. These latter should 
be perfectly smooth below, and should be of considerable 
thickness. They are prepared of the proper thickness 
in the following manner : A fine thin sheet of tin-foil is 
first pressed into all the cavities of the original plaster 
mould, so as to give a reversed copy of it, and a plate of 
softened wax of the desired thickness of the metal plate, 
is forced into it so as to take its form. A plaster mould 
is then taken of this wax impression, covered with tin- 
foil, and the model and the mould, placed parallel to each 
other, are separated by little leaden tubes, which are equal 
in height to the thickness of the wax-plate before used. 

In order that the casting should be successful, the 
plaster models and moulds must be perfectly dry, and 
heated to the temperature of the fused alloy, and when 
filled must be placed in a position to cool rapidly. 

The large compound plates are exposed, in stamping, 
to the action of heat by means of pipes conveying steam, 
placed below them. 

Two means of stamping leather with figures in relief 
are resorted to, that by use of the press, and that in 
which the stamping is effected by hand or the chisel, 
with the assistance of heat. The leather is first fulled 
in tepid water, until it becomes as soft as it is possi- 
ble to make it. In this condition it is placed upon the 
plate without being stretched, and is made to enter 
all the depressions of the figures by pressing and squeez- 
ing it in every direction with the fingers, while the pro- 
jections and folds upon the edges of the design are 
smoothed down by a wooden instrument like the chisel 
used by sculptors. When the leather is in contact with 



684 APPARATUS USED BY LEATHER MANUFACTURERS. 

all parts of the mould or plate, if the character of the 
figures is such as to admit of perpendicular pressure, the 
frame is filled up with warm sawdust, and. the gentle 
force of a press is applied above, so as to keep the leather 
and metal surfaces in contact. After a time, the screw 
is loosened, the moistened sawdust is removed, and re- 
placed with fresh, the press is again brought to bear, and 
this process is repeated once more. At the end of the 
third operation, the leather will generally have acquired 
enough consistency to retain the form impressed upon it, 
and it may then be removed from the plate and dried in 
the stove-room. 

If the plate be too large for the press, or if there are 
many projections on its surface, having slight or nar- 
row bases, the pressure must be conducted entirely by 
hand. For this purpose the plate is warmed by placing 
it upon the tubes conveying hot air or steam, and the 
moistened leather is laid upon it, and forced down into 
all the depressions and grooves of the plate by means of 
paper-hangers' paste, which is thrust and pressed down, 
into them with the end of the wooden instrument or 
chisel, and when the chief cavities are filled in this way, 
the rest of the surface is worked so as to bring the 
leather in contact with the plate in every part. The 
folds which form at the borders and corners are then 
smoothed out with the chisel, first longitudinally, and 
then across, until they are made to disappear. The whole 
surface of the leather is then rubbed with a dry sponge 
so as to remove the excess of moisture, and the workman 
then continues forcing it down into the depressions with 
a chisel, until it is perfectly dry, when the rest of the 
paste is removed from the hollows. The elasticity of the 
leather, when dry, allows of its removal from the plates 



BERNHEIM AND LABOURIAU'S PROCESS. 685 

even when the elevations on the latter are larger at top 
than at bottom. 

If it is intended to stamp a design, or series of designs, 
the dimensions of which require the use of a number of 
skins, the latter are first cut into parallelograms, and their 
edges are pared and thinned down. One of them in the 
softened state is then placed at an angle or edge of the 
plate, and is impressed with the figures in the manner 
before described. A second skin is then placed alongside 
of the first, with one edge projecting about an inch over 
its border, and is printed in the same w^ay ; a third is 
placed next to and partly over the second, and so on, 
even if a number of rows of skins are required, until the 
whole extent of the plate is occupied. After the skins 
have all been pressed, sponged, worked with the chisel, 
and dried, their overlying edges are gently raised, cov- 
ered with strong glue, carefully replaced, and retained in 
their original position, by covering the whole with saw- 
dust and weighted planks, until it dries and forms a con- 
tinuous sheet. 

By these two processes, leather beautifully ornamented 
in relief, and suitable for many purposes of luxury, may 
be manufactured. These ornaments may be allowed to 
retain, in a slight degree, the suppleness and elasticity of 
the leather, or may be rendered perfectly firm and hard, 
by pouring into them, while still warm upon the castings, 
a solution of gum-lac in alcohol, or a watery solution of 
glue, and filling up all the depressions with paste, saw- 
dust, or, what is still better, the raspings of cork mixed 
with glue. Their surfaces may be made impervious to 
moisture, by the penetration of the gum-lac or of other 
resinous material, and may be painted, gilded, and var- 
nished. 



666 APPARATUS USED BY LEATHER MANUFACTURERS. 

F. W. East's Process. 

This invention, patented in 1851, differs from the 
usual method in being exclusively applicable to the flesh 
side of leather, and thus producing an effect superior to 
that obtained by embossing the grain side. It is adapted 
to all tanned skins except those which are oil-tanned. 

The skins, just sufficiently shaved to remove flaws and 
give them uniform thickness, are to be immersed in water 
of 120° F., and brushed on the flesh side to remove dirt 
and open the fibre. They are then to be folded grain- 
side inwards and the edges sewed together in bag form, 
so as to prevent the intrusion of the dye. The dyeing 
succeeds " scouring" and " sweetening," and is effected 
with much weaker liquors than are used for dyeing the 
grain side of skins ; but requires a longer, time, as the 
process must be several times repeated in order that the 
color may penetrate the fibres, and appear uniform. 
They are then rinsed, opened, and dried. 

When dry, they are to be " perched" on the flesh side 
with a moderately sharp knife, so as to soften the fibres, 
and nap the surface without cutting the flesh off. Each 
skin is to be again folded as before, and passed through 
a glutinous solution of one part, by measure, of size in 
three parts of water; then stretched on boards to dry, 
trimmed around the edges, and bruised on the surfaces 
with cork, to render them soft, the flesh side being kept 
outwards. 

The skins, just previous to being embossed, are moist- 
ened on the grain sides with clean water, and then laid 
together, with the grain sides in contact, and under cover 
in order to prevent access of air, and thus to promote 
the thorough penetration of the water through the hide, 
thereby making the gelatinous matter auxiliary to the 



DEGRAND S MACHINE. 



687. 



production of a gloss upon the embossed parts. The 
embossing is done with engraved rollers, previously 
heated to 250°, and exactly in the same manner as is 
employed for embossing velvet, cloth, &c. 



CHAPTER CLXXI. 

DEGRAND'S MACHINE FOR SPLITTING AND SHAYING 

LEATHER. 



A TRANSVERSE section of Degrand's machine is shown 

k 

Fig. 19t. 



in Fig. 197. A horizontal knife a, longer than the 




KaA^ 



greatest width of a skin, is fixed upon a wooden table 
B. A cast-iron plate h is set in the table in front 
of the knife-blade, and is intended to support the leather 
c at the desired elevation, its position being regulated 
by screws and nuts. It is movable in every direction, 
being supported upon four springs. Above it, a little 
wooden shelf d, which is pressed upon by a roller e, 
maintains the leather in close contact with the plate, so 
as to flatten and stretch it thoroughly before it is exposed 



688 APPARATUS USED BY LEATHER MANUFACTURERS. 

to the blade. One of the separated surfaces of the lea- 
ther, as it rises over the knife, is attached to a wedge- 
shaped tongue, which projects from the whole length of 
the wooden roller c, and is wound up upon the latter as 
it advances. 

The leather is seen in the figure as split by the blade 
of the knife, the upper portion of it being already rolled 
upon the cylinder c. The lower half passes down under 
the knife through a slit in the table, and the uncut por- 
tion, which is about to be exposed to the action of the 
blade, is seen resting upon the table, and pressed down 
by the upper plate d. The movement of revolution is 
given to the cylinder by a winch which turns a pinion 
gearing with a toothed wheel at one of its ends. Two 
operations are required to split the leather, one-half of 
it being first separated, the skin being then unrolled from 
the cylinder, turned, and the split part attached to it, so 
that the other half may be in like manner divided.* 



CHAPTER CLXXII. 

GIRAUDON'S MACHINE FOR SPLITTING AND SHAVING 

LEATHER. 

This interesting invention has been described by M. 
Armengaud, in the PMication ladustrielle des Machines, 
oiUiJs et appareils, t. vi. liv. 9. The machine is simple 

* The author has omitted to explain the mode of forcing the edge 
of the leather upon the knife-blade, by which the first part of the in- 
cision is effected. The process can only be rationally understood by 
supposing that a longitudinal incision is first made down the centre of 
the skin extending half through in thickness, and that, while one edge 
of the skin is attached to the roller, the knife is accurately engaged in 
the bottom of the cut previously made. 



giraudon's machine. 



689 



in construction, operating rapidly and continuously upon 
the skins exposed to its action, and can be employed 
either for the purpose of dividing the leather into thin 
sheets or leaves, or for that of diminishing and equalizing 
its thickness. 

Fig. 198. 




Fig. 199. 




The hide or skin which is to be cut is placed upon the 
circumference of a large drum or cylinder A (Figs. 198, 
44 



690 APPARATUS USED BY LEATHER MANUFACTURERS. 

199, and 200), carefully turned and attached to three 
crosspieces with six branches or spokes b, which are con- 
Fig. 200. 




nected with the cast-iron horizontal shaft c. This cylin- 
der is hollowed out, as seen in the section shown in Fig. 

Fig. 201. 




201, for the reception of a kind of pincers d (Fig. 207), 
which serve to support the extremity of one of the de- 



giraudon's machine. 



691 



tached portions of skin against the edge of the cylinder. 
For this purpose, these pincers are all mounted upon the 
same iron axle a, which rests upon small supports h, 
fastened to the cylinder, and they are kept in place by 
a flat, angular regulator. 

The horizontal shaft C, which extends on each side 
beyond the cast framework e, carries at one end the 



Fig. 202. 



Fig. 203. 





larger cog-wheel f, which is geared with the endless 
screw e (Figs, 202 and 203), situated at the lower part 



Fig. 204. 



Fig. 205. 




Fig. 206. 



2.1 



of the machine, and revolving upon the axle /, the slow 
movement of which is produced by means of the wheel 
G, the endless chain g, and the pinion h. 
This pinion turns upon the cast-iron shaft Fig. 207. 
H, which is made to revolve by means [. .^ . 3 
of a strap passed over one of the pul- ac=^ 
leys i; a fly-wheel J giving the neces- 
sary uniformity to the motion. A roller 
i, at the end of a counterpoised lever /, 



692 APPARATUS USED BY LEATHER MANUFACTURERS. 

presses against the endless chain, and gives it the proper 
amount of tension. 

The shaft h is elbowed in the middle, so as to form a 
crank for the head of the cast-iron rod K, which is 
articulated at its other end with the middle of the mov- 
able rabbit or carriage L (Figs. 201 and 204). At the 
base of this is attached the long cutting steel blade which 
is inclined a little in direction to the horizon, and 
touches the exterior of the cylinder when made to ap- 
proach it. It is very thin and of an undulating form, as 
shown in the plan (Fig. 205), so as to act upon the leather 
like a saw, the teeth of which are rounded off; by which 
arrangement it cuts more easily and with less wear of 
edge. This knife-blade is attached to the base of the 
rabbit by means of an iron plate m, the position of which 
can be accurately adjusted with a screw. 

The movable rabbit or carriage is dove-tailed into 
the tops of two cast-iron supports E, which compose the 
framework. The grooved plates n above it prevent any 
deviation from the reciprocating rectilinear movement 
produced by its connection with the crank. Thus the 
shame shaft h which moves the crank causes the revolu- 
tion of the lower axle/, and of the endless screw, by 
means of which the drum upon which the skin is wound 
is also turned ; but with a motion exceedingly slow, when 
compared with that of the crank above, and the knife 
connected with it. The ratio of size between the 
pinion h and the wheel G being as one to eight, and the 
large wheel f having 244 teeth, it follows that the 
cylinder only turns once while the axle / and the end- 
less screw are making 244 revolutions, and the main 
shaft H is making 1952. By causing the main shaft to 
revolve 75 times in a minute, the knife is made to cut 



giraudon's machine. 693 

the leather 150 times, so that a skin 78.74 inches in 
length will be split in 15 J minutes. 

The leather is maintained in close contact with the 
cylinder in front of the knife-blade by the pressure of a 
series of flexible spring-keys which adapt themselves to 
its irregularities of surface, and keep its uncut edge 
firmly pressed down by means of a crosspiece extending 
along its whole breadth and supported by projections 
upon the inside of the framework. A strong bar g 
serves to support the other ends of the springs, and also 
assists in keeping the leather applied to the surface of 
the cylinder. Two grooved uprights y are adjusted in 
rectangular vertical mortises of the framework, and the 
screws x, in their lower parts, regulate the height of the 
bar. 

The lower separated portion of the split leather re- 
mains in contact with the cylinder while it revolves, 
and the upper part may be rolled oflf, if desired, upon a 
roller placed above the machine. 

When a skin is divided throughout, in order to replace 
it by a fresh one, it is necessary to lower the cjdinder 
from its position, in order to disengage the knife from 
the surfcices. For this purpose, the cushions r of its 
axle are adjusted in movable collars supported upon 
uprights 8 and s', which can be elevated or lowered by 
means of iron swipes t, which are supported upon the 
base of the framework E, and are connected by a cross- 
bar, or treadle, which the workman can lower by a pres- 
sure of his foot, the collars and uprights being only mov- 
able in a vertical direction. In order that the cog-wheel 
and the screw may continue in gear during this change 
of position, the cushions which support the axle of the 
latter are connected with the crossbar between the two 
uprights. 



694 APPARATUS USED BY LEATHER MANUFACTURERS. 

The revolution of the cyUnder can be stopped at plea- 
sure by ungearing the wheel e, which can be moved 
upon its axle by the handle u and fork v. 

Thirty-six raw hides can be readily divided by this 
machine in a day of twelve hours. 



CHAPTER CLXXIII. 

MACHINES FOR SPLITTING AND SEATING LEATHER. 

Eicharpson's Machine, invented by Alpha Richard- 
son, of Massachusetts, is generally used throughout the 
United States. It serves for splitting either green or 
tanned hides. There are two modifications, that shown 
in perspective, by Fig. 208, is intended for splitting 

Fig. 208. 




upper leather, which is drawn between the knife and 
roller by means of a crank and windlass. This is styled 
the Tanner and Curriers' Machine. A is the cast-iron 
piece connected with the gauge-roller B, which revolves 
on the centres e e, and is turned up by the lever o, to 



SPLITTING AND SHAVING MACHINES. 



695 



allow the placing of the leather upon the top of the knife 
and back-spring A A, The skin being in right position, 
the gauge is then turned back, and forms the gauge for 
the thickness of the skins which may be regulated at 
will, by means of the screws Ji h. B is the roller with 
the sectional tubes g g g, which are arranged to turn on 
its end, and to serve as friction-rollers when the shanks 
and loose part of the skin are being drawn through. 
The knife D is bolted, firmly, to the bed by the screws 
Hi i. The leather is placed upon the cylinder G, and 
drawn through against the knife D by the aid of the 
crank at the end of the machine. 

The leather is prepared for splitting b}^ being only 
partially dried. In New England and in the middle 
States it is generally split before it is wholly tanned, as 
the quality of the leather is thought to be improved by 
finishing the tanning after it has been thinned or divided 
by the machine. 

The other modification of the machine is constructed 
for splitting and skinning sole leather, welt leather, and 
stifi'enings for boot and shoemaker's use. It is repre- 
sented by Fig. 209, and works by means of rollers which 

Fig. 209. 




force the leather against the edge of the knife. A is the 
gauge-roller, which is regulated by screws according to 
the thickness it is desired to split the skin. B is the 



696 APPARATUS USED BY LEATHER MANUFACTURERS. 



lower roller, which forces the leather, or hide, against 
the knife, and the two are put in motion by the crank, 
&c., at the end. The leather must be damped through 
before being placed in the machine. 

Seguin's Shaving and Smoothing Machine. — This 
machine consists of two metallic rollers, each six feet six 
inches long ; one of them five and nine-tenth inches in 
diameter, having a cutting-blade set spirally into its 
surface, and intended to pare the skin wrapped around 
the other roller, which is two feet five inches in diameter. 
A longitudinal groove in the surface of the lower roller 
receives the end of the hide, which is kept in place by 
means of wedges. The cutting-blade begins to form a 
spiral at the middle of the upper roller, and makes the 
entire circuit on both sides before reaching the ends. 
The pivots of the lower roller turn in two fixed supports, 
and those of the upper one in two levers, by means of 
which it can be lowered upon, or raised from the surface 
of the first one. These rollers turn in opposite direc- 
tions, and their motion is so adjusted that the lower one 
turns completely around once, while the upper is mak- 
ing twelve revolutions. 

The end of the leather having been engaged in the 
groove, it is gradually wound upon the roller, while the 



Fig. 210. 



Fig. 211. 





levers upon which the upper roller turns being charged 
with smaller or greater weights, as the case requires, 
the skin, with its grain side up, is shaved from the centre 



SPLITTING AND SHAVING MACHINES. 697 

to the sides, throughout its whole extent. Fig. 208 is a 
front view, and Fig. 209 a side view of this machine. 
H, the lower roller, with the horizontal groove a for the 
end of the leather; i, upper roller, with the blade 5, 
curving spirally from the centre ; k, lever carrying the 
roller, and supported by the crosspiece l. 

Chapman's Improved Leather Splitting Machine. 

The annexed engraving represents an improvement 
for getting the most possible surface out of a given 
weight of leather, and splitting the thick hides into 
two thinner sheets. 

A thin circular knife c (Fig. 213), made dishing with 
the convex side uppermost, is made to revolve by suita- 
ble machinery, with its sharp edge just above a hori- 
zontal table D, and the leather to be split is drawn over 
this table against the edge of the revolving knife. The 
lower sheet o of the split leather passes down below 
the knife around the feed roller f, to which it is secured 
by the clamping bar/. The leather is drawn along and 
pressed against the edge of the knife by the rotation of 
the feed roller f, which is turned by the machinery at 
the proper speed for this purpose. The upper sheet p 
passes above the knife and is removed by hand. A 
series of springs G, with their ends curved to fit near the 
cutting edge of the knife, are placed above the leather 
to hold it down close to the table. The shaft which 
carries the knife rests upon a stiff spring at the bottom, 
and is pressed down by a set screw at the top, by which 
means its distance above the table may be regulated and 
the thickness of the lower sheet of leather varied at 
pleasure. The table has racks d secured to its lower side, 
which racks mesh into pinions i, the shaft of the pinions 
having a crank upon its end. By this means the table 



698 APPARATUS USED BY LEATHER MANUFACTURERS. 



Fig. 212. 




may be drawn back from the edge of the knife, for the 
purpose of placing the sheet of leather to be split upon 
it. After the leather is placed, with one end secured to 
the feed roller, the table is carried up to the knife, the 
machine started, and the operation proceeds. This in- 



SPLITTING AND SHAYING MACHINES. 



699 



Fiff. 213. 




genious machine was invented by H. E. Chapman^ 
Albany, New York. 



Introduction of Splitting Machines into German heavy and 
upper Leather Tanneries^ 

The opinions of tanners in Germany upon the de- 
sirability of the employment of leather splitting ma- 
chines for heavy and upper leather are widely different. 
Some who have seen them in operation or actually 
employed them in their own business are satisfied, while 
others declare them in advance to be unsuited to the 
proposed object, and many who have bought such ma- 
chines are willing to dispose of them at a loss. These 
splitting machines have either been introduced from 
abroad, especially from America, or they have been con- 
structed at home chiefly after the American models, but 
pot much has hitherto been made public concerning the 
practical working of the same. The reason of this, after 
allowing for the strong antipathy leather- makers have to 
writing, lies partly in the fact that those who after much 

* By P. A. Gunther. Gerber Zeitung. 



700 APPARATUS USED BY LEATHER MANUFACTURERS. 

pains have at last become satisfied with the execution 
of the splitting machine, do not desire, from motives easy 
to be understood, to promote its spreading by their in- 
dorsement, and again in this that such as are not con- 
tent with the machine and its execution, although they 
confess to themselves their errors in judgment, will not 
publicly admit it in a report, fearing to write that they 
have deceived themselves. The meetings of union Ger- 
man tanners have already several times afforded oppor- 
tunities to see machines of German make in operation. 
We first saw such a one at the general meeting at Dres- 
den constructed by M. Wilsdorf upon an American 
model. The second was one exhibited by the Wamosy 
tannery at the Hamburg meeting, and at the meeting 
recently held at Eisenach we saw another of Wilsdorf 's 
American machine, having many improvements of his 
devising ; but owing to the late date at which it was 
sent to the exhibition, only a few saw it in operation. 
In our opinion, however, a couple of hours' experiment- 
ing is not enough to form an accurate judgment of the 
worth or working capacity of a machine like this, which 
is always so complicated and so difficult to manage. 
The operator must understand thoroughly the working 
of the machine in order to produce satisfactory results. 
The best machine, unless worked by an adept, will give 
imperfect results. The manifold inquiries that have been 
addressed to us by members of the trade, we could only 
reply to in this ineflicient manner ; for the goods sent 
to our leather establishment for split goods showed only 
too clearly the great importance of the proper working 
of these machines, and we have remarked with interest 
how, through greater practice, the goods of the same 
shippers have gradually grown better and better, until 
they finally thoroughly answered the requirements of 



SPLITTING AND SHAVING MACHINES. 701 

consumers. From the purchaser of the splitting machine 
exhibited at Eisenach, M. J. Dritzen, a Rhenish white 
leather tanner, we recently received a communication 
regarding the operation of his splitting machine which 
may be of interest to our readers. 

" I first became acquainted with the splitting machine 
in America, in 1849, at which time I was with Schafer 
& Co., in Pittsburg, Pa. They use it there to split large 
heavy ox-hides into three parts. The grain was used 
for carriage-tops, and it was lacquered ; the middle por- 
tion, also lacquered, was employed for various purposes, 
and the last third, the fleshy part, was dressed for 
upper leather. Since then other business took my at- 
tention from tanning, until the summer of 1861, when 
personal matters induced me to return to it. 

" As a tanner having in mind the great lever of in- 
dustry, the division of labor, I decided upon upper leather 
tanning, without on this account removing the advan- 
tages offered to me in my position by the small leather 
trade, with the consumers of the neighborhood. I pur- 
chase the various descriptions of leather necessary for 
the latter branch of my business at the large markets, 
while I appear at the same time upon the same markets 
with my own manufacture as a seller. And thus I am 
in a position to restrict myself to one single article as a 
manufacturer, to perfect my means of producing the same, 
and to concentrate my labor and attention upon one 
single point. 

" My object consists, by selecting the best possible raw 
material, and by working the same in the most suitable 
manner, in producing a prime article which will leave 
me a clear profit at any large market. In this connec- 
tion I recollected the American splitting machine which 
appeared the more suitable to me as tlie hides in my 



702 APPARATUS USED BY LEATHER MANUFACTURERS.' 

section possess very compact layers. I became acquainted 
with the constructor of the splitting machine, and from 
him I got the machine exhibited at Eisenach. The 
maker gave me instructions on the spot in the manipu- 
lation of the machine, using a single hide for the purpose, 
and in the same time he agreed, in case I should not be 
able to work it readily, to give me more thorough in- 
structions upon a few dozen of hides. But the neces- 
sity for this did not hccur. I put up the machine myself, 
and gradually have acquired the necessary dexterity in 
splitting, although not without paying for it, that is, after 
having damaged a dozen hides more or less. Its mani- 
pulation is not difficult, but it requires practice, and 
much of it before one attains to proficiency ; still I must 
not omit to mention that with a little precaution, the 
damage done by the machine, except to the grain side, 
leather is not essentially injurious. When the splitter 
lets the knife cut the hide improperly small hollows or 
noses as they are called are made, and sometimes also, 
but rarely, holes ; but by skilful handling the machine 
gives splendid results. 

" I work into upper leather generally' hides weigh- 
ing 35 lbs. green weight. Such a hide split, so that 
brisket and butt are of equal solidity, yields me from 
13 to 14 lbs. of well-tanned, well-dried, and slightly 
fatty leather, and a split weighing two or three pounds 
which I hitherto sold at the best price. M3'' customers 
are quite satisfied with the durability of the new sort of 
leather. The only thing that the leather, especially the 
split, loses, is the grain and consequently the softness, 
and on this account it is particularly suitable for the 
hinder parts of boots. The advantage in my opinion 
consists principally in this, that I can split white leather 
thin, and thus obtain a more valuable article, without its 



SPLITTING AND SHAVING MACHINES. 703 

being essentially injured, for as I work my leather 
strongly I gain a more valuable split. I split my leather 
during the process of tanning, after the hide has re- 
ceived half of the tan liquor. The more the leather is 
tanned the easier the splitting knife cuts, and the jSner 
and smoother is the bisection. M. Knoderer, of Stras- 
burg, to whom I made known my intention of buying a 
splitting machine, advised me to select one with which 
I could cut my hides in the beginning while they were 
yet in the lime. He assured me that all the great manu- 
facturers of France bought such machines only ; but the 
matter of expense restrained me from following this coun- 
sel, as such a machine cost $720. 

"However, they possess important advantages over 
others. By their employment the process of tanning is 
accelerated and a considerable economy in tanning ma- 
terial is effected. A large amount of hide cutting, which 
is now useless to me, being only half tanned, could be 
turned to account as glue. But, as I have said, my 
financial position did not allow me to procure such a ma- 
chine. 

" In conclusion, I would call special attention to the 
following in answer to the erroneous opinion that split- 
ting machines are only adapted to large establishments. 
My business is a very small one. I tan yearly only 
from 400 to 600 pieces of white dressed skins, but I 
hold that a limited trade is better than an extensive, 
that, therefore, a tanner had better devote one-half of 
his capital to the procurement of suitable apparatus and 
keep an inn with the other half than to avoid ma- 
chines and other suitable apparatus, and only produce 
goods in large quantities." 



INDEX. 



A 



Age of trees relatively to the richness 
of their bark in tannin, 113 

Albumen, 169, 172 

Aldrich's apparatus, 403 

Alumed skins, 564 

Aluming hides, 619 

Animal oils, 615 

Apparatus used by leather manufactu- 
rers, 653 

Ash bark, 104 



B 



Barks, 96, 98 
Bark, ash, 104 
birch, 103 
beech, 103 
black-thorn, 103 
chestnut, 103 
chopping machine, 146 
Birely's, 159 
Bourgeois's, 150 
Farcot's, 146 
Lespinasse's, 153 
Wiltse's, 155 
cinchona, 104 
cinnamon, 101 
containing the most tannin, parts 

of the, 112 
elm, 104 

estimation of the value of, 123 
chemical process, 123 
Bell Stephens', 125 
Davy's, 125 
Gerland's, 131 
MuUer's, 126 
Warrington's, 124 
hemlock, 107 
horse-chestnut, 103 
Lombardy poplar, 103 
oak, 107 

American, 110 

45 



Bark — continued. 

oak, black, 110 
European, 108 
white, 110 

poison-oak, 104 

pomegranate, 103 

proportions used, 252 

sassafras, 102 

sumach, 104 
. tamarisk, 107 

wild olive, 104 

willow, 106 
Barking of trees, 112 

most convenient time, 113 

influence of the season and place 
at the time of, 115 
Baron's process, 481 
Beam, marking on the, 237 
Beating of leather, 257 

and rolling by machinery, 257 

Bell's process, 480 
Berendorf's machine, 270 
Berenger & Sterlingue's process, 371 
Bernheim and Labouriau's process of 

embossing, 682 
Elet's process, 481 
Bunting's process, 476 
Burbidge's process, 393 



Calf-skins called alumed skins, 564 

classification of, 295 

currying of, 522 

English, 525 

grained, 556 

leather for belts, 557 

oiled, 522 

tallowed, 524 

tanning of, 291 

waxed, 293, 526 
Catechu, 78, 82 

Chapman's improved leather-splitting 
machine, 697 



706 



INDEX. 



Chestnut bark, 103 
Cinchona bark, 104 
Cinnamon bark, 101 
Cochran's process, 475 
Color of red Russia leather, 584 
Common russet, 521 
Cordovan leather, 333 
Cords from intestines of sheep, manu- 
facture of, 645 

clock-makers', 648 

different, 647 

hatters', 648 

m.usical instruments, 643 

rackets, 647 
Corniquet's process, 379 
Cox's machine, 275 
Cuirs a murou leather, 425 
Currying, 487 
• calf-skins, 522 

goat-skins, 571 



D 



Daniel's process, 478 
Danish process, 339 
D'Arcet's process, 366 
Decrease in weight of bark when ex- 
posed to the air, 115 
Degrand's machine for splitting and 

shaving leather, 687 
Depilation by caustic soda, 204 

steam, 203 

sulphuret of calcium and soda, 204 
Desmond's process, 393 
Dietz's process, 477 
Dipping, 488 

Disinfection of workshops, 642 
Distillation, of the empyreumatic oil 

of the birch-tree bark, 578 
Divi-divi, 93 
Drake's process, 398 
Dressing, bran, 225 

decomposition of the white, 226 

method of working the, 223 

rye, 227 
Drying hides, 622 

leather, 253 
Dunseith's process, 473 



E 



East's process of embossing, 686 
Eggleston's process, 476 
Ellagic acid, 65, 71 
Elm bark, 104 
Embossing of leather, 682 



English calf-skins, 525 

hides, 518 

process, 391, 443 
Epidermis and cutis, with reagents, be- 
havior of the, 167 
Excrescences containing tannin, 86 
Exposure to the air, 629 
Extractive, 73 



F 



Fibrin, 169 

Flaming, 628 

Flint hides, 368 

Flotard & Delbut'a machine, 269 

Flowers, 88, 91 

and flower tops, list of, 94 
Fruits, 88, 91 



G 



Gallic acid, 65 

chemical properties of, 65, 68 
composition of, 65 
preparation, 65, 66 
Braconnot's, 66 
Fiedler's, 66 
Scheele's, 66 
Ure's, 67 
Gelatin, 169, 171 
Giraudon's machine for splitting and 

shaving leather, 688 
Glossed leather, process to prepare, 354 
Goat-skins, bleaching, 326 
currying, 571 
tanning, 322 
Goldbeater's-skin, 643 
Grain black, 506 
Grained calf-skins, 556 
Greases, 615 

Greasing tanned hides, 557 
Guiot's process, 483 
Gut-dressing, 637 



H 



Halvorson's process, 461 

Hannoye's process, 433 

Harness-makers, leather for, 569 

Harper's process, 479 

Hatch's process, 420 

Heald's apparatus for tanning hides, 

247 
Hemlock bark, 107 

tanning, 456 
Hibbard's process, 454 



INDEX. 



707 



Hides, aluming, 619 

English, 518 

greasing tanned, 557 

liippopotamus, 181 

horse, 178 

ox, 177 

proper treatment of, 173 

raising, 195 

salting, 173, 181 

soaking of foreign, 186 

stacking, 198 

tallowing, 624 

treading, 623 
Hill's process, 480 
Horse-chestnut bark, 103 
Horse-hides, tanning of, 335 
Hungary leather, 613 

defects in the quantity of, 634 

improvements by Curandeau, 636 

Kresse's process of preparing 
black, 633 

made of cow and calf-skins, 631 
horse-hides, 631 

uses, 635 



Indian method of preparing elk-hides, 
419 

Introduction, 17 

Importation of hides at Boston for 1863, 
24,25 
at New York for 1863, 22, 23 
at Philadelphia for 1863, 26 
at Salem for 1863, 26 
for the past sixteen years, 21 

Irish process, 425 



Jahkel's process, 569 
Jennings's process, 370, 611 
Johnson's process, 447 



E 

Kalmucks' process, 427 

Kennedy's process, 474 

Kid, imitation, 466 

Kino, 78 

Kips, 178 

Kleman's process, 394 

Knowlis's process, 402 



Lacker for shoes and leather belts, 

black, 604 
Lamb-skins, method of coloring small, 

467 
Lathe-cords, 644 

from intestines of sheep, 645 
Lard, 615 
Leather, 165 

action of frost on, 282 

beating, 257 

and rolling, 259 

belt, 284 

bottles, 338 

Cordovan, 333 

cow, 288 

cuir a muron, 425 

defects of the, 280 

drying of the, 253 

with grease, saturation of, 563 

harness-makers', 562 

Hungary, 613 

machine for finishing, 661 
for rolling green, 653 

method of coloring white tawed, 
469 

morocco, 329 

oil, 510, 515 

patent, 600 

preparation of stretched, 498 
of sleeked, 499 

process to prepare glossed, 354 

proximate principles of, 165 

quality of, 280 

red, 339, 590 

Russia, 575, 583 

tallowed or grained, 504 

Transylvania, 227 

Turkey, 429 

Wallachia, 219 

water, 510 

water-proof, 610 

waxed, 518 

white, 521 
Leaves, 88 

list of tanning, 89 
Leprieur's process, 360 
Lime process, inconveniences of the, 

201 
Lombardy-poplar bark, 103 



M 



Machine, Chapman's improved leather- 
splitting, 647 
Cox's, 275 
for chopping barks, 138 



708 



INDEX. 



Machine — continued. 

for rolling green leather, 653 

finishing leather, 661 

Flotard & Delbut's, 264 

pressing, 270 

Richardson's, 694 

Seguin's, 279 

for shaving, 696 

Wiltse's, 277 
Male fern, 96 
Marsh rosemary, 97 
Marking, 630 

Method of estimating the tanning power 
of astringent substances, 123 

of making leather water-proof, 611 
Mill for grinding oak-bark, 143 
Morocco leather, 329 
Mutton suet, 615 
Myrobalans, 93 



N 



Needham's process, 479 

Nenory's preparation to render leather 
water-proof, 607 

Newton's process, 367 

Nisbet's grounding and pumicing ma- 
chine, 678 

Nossiter's process, 438 

Nuessley's process, 480 

Nutgalls, 86 







Oak-barks, 107 
American, 110 
black, 110 
European, 108 
poison, 104 
white, 110 
Odoriferous substance of the birch-tree 

bark, nature of, 582 
Ogereau's process, 390 
Oiled calf-skins, 522 
Oils, dolphin, 617 
fish, 616, 618 
porpoise, 617 

process to give to a mixture of 

different oils the properties of 

fish, 618 

process for rendering vegetable 

oils to take the place of fish, 618 



Parchment, 592, 595 



Patent leather, 600 

Perkins's machine for pommelling and 

graining leather, 675 
Piling, 630 
Plants containing tannin used as a 

substitute for oak-bark, 117 
Poison-oak bark, 104 
Pomegranate bark, 103 
l^ommelling, 493 

Preparation of the intestines of cattle, 
637 

operation, 638 
Process, American, 391 

D'Arcet's, 366 

Baron's, 481 

Bell's, 480 

Bletz's, 481 

Berenger & Sterlingue's, 371 

Bunting's, 476 

Burbidge's, 393 

Cochran's, 475 

Corniguet's, 379 

Daniel's, 478 

Danish, 339 

Desmond's, 393 

Dietz's, 477 

Drake's, 398 

Dunseith's, 473 

Eggleston's, 476 

English, 391, 443 

Guiot's, 483 

Halvorson's, 461 

Hannoye's, 433 

Harper's, 479 

Hatch's, 420 

hemlock, 456 

Eibbard's, 454 

Hill's, 480 

improved, 352 

Indian, 419 

Irish, 425 

Jahkel's, 569 

Jennings's, 370, 611 

Johnson's, 447 

Kalmucks', 427 

Kennedy's, 474 

Kleman's, 394 

Knowlis's, 402 

Leprieur's, 360 

Needham's, 479 

Newton's, 367 

Nossiter's, 438 

Nuessley's, 480 

Ogereau's, 390 

quick, 482 

Eobinson's, 476 

notch's, 399 

Seguin's, 352 

Shakers', 458 



INDEX. 



709 



Process — continued. 

Smith & Thomas's, 506 

Spilsbury's, 39() 

Squire's, 442 

Snyder's, 452 

to tan with decoction of oak-bark, 

391 
tanning leather in Russia, 586 
Thompson's, 476 
Tumhull's, 447 
Vauquelin's, 380 
Webster's, 475 
Wells's, 475 



Quick process, 482 
tanning, 471 



R 



Raising by acids, 202 

by barley, 210 

by sour tan-liquor, 228 

by yeast, 236 
Red leather, 339, 590 
Residues and products of tanneries, 484 
Rhatany, 97 

Richardson's machine, 694 
River work, 618 
Robinson's process, 476 
Roots, 96 

Rotch's process, 399 
Russet, common, 521 



S 



Sassafras bark, 102 

Seeds, 88, 95 

Seguin's machines, 279, 696 

process, 352 
Shagreen, 592 
Shakers' process, 458 
Shaving, 492 

improved machine, 696 
Sheep-skins, tanning of, 322 

coloring of, 327 
Skin, 165 

calf, 178 

composition of the, 169 

constituents of the, 169 

deer, 181 

goat, 180 

gold-beater's, 643 

pig, 181 

porpoise, 181 



Skin — continued. 

preliminary treatment of, 183 

seal, 181 

sheep, 179 

structure of the, 165, 166 

suitable for tanning, 173, 176 

treatment of, 173 

washing, 183 
Smith & Thomas's process, 606 
Smith's leather polishing machine, 673 
Spilsbury's process, 396 
Splitting machine, 694 

in Germany, 697, 699 
Squire's process, 442 
Stretching, 494 

hides, 622 
Sumach bark, 104 
Sweating process, 208 
Synder's process, 452 



Tallow, 616 

Tallowed calf-skins, 624 
Tallowing, 624 
Tamarisk bark, 107 
Tan, 41, 137' 

liquor, preparation of the, 233 
vats, 239 
Tannin, 41, 44 
artificial, 61 

composition, 61, 62 
first variety, 61, 62 
properties, 61 
second variety, 61, 63 
third variety, 61, 63 
turf, 61, 63 
of bark of trees, 59 
black precipitate in sesqui-salts of 

iron, 60 
catechu, 59 

chemical properties, 44 
composition, 44, 50 
contained in principal tanning 

substances, 134 
green precipitate in sesqui-salts of 

iron, 60 
impure, 53 

chemical properties, 53 
preparation, 53, 55, 56, 57, 58 
I varieties, 53, 58 

from various sources, 64 
Tanning, 183 
, Aldrich's apparatus, 403 
•' calf-skins, 291, 444 

chemical researches on the art of, 

344 
chemistry of, 41 



710 



INDEX. 



Tanning — continued. 

with decoction of oak-bark, 391 

different skins, 337 

extracts, 161 

Connel's, 161 
Steers's, 162 

goat and sheep-skins, 322 

with grape skins, 357 

hemlock, 456 

hides, Heald's apparatus for, 247 

horse-hides, 335 

juices, 78 

lamb-skins, method of, 467 

materials, 76 
table, 77 

with myrtle, 356 

origin and development of the art 
of, 31 

processes, 239 
of Leprieur, 360 

quick, 471 

saps, 78 

sheep-legs, 337 

with statice, 358' 

substances necessary to tan an 
equal quantity of leather, com- 
parative quantities of different, 
136 

with tar and soot, 417 

theory of, 340 

time necessary for, 251 

wheel, 413 



Tawed leather, method of coloring, 469 

Tawing, 463 

Tea, 88, 90 

Thompson's process, 476 

Transylvania leather, 227 

Treading hides, 623 

Turkey leather, 429 



Valonia, 91 

Vauquelin's process, 380 
Varnishing leather for belts, 605 



W 



Wallachia leather, 219 
Water, 192, 193 

upon the quality of the leather, 
influence of, 191 
Water-proof leather, 606 
Webster's process, 475 
Weighing, 630 
Wells's process, 475 
Wild-olive bark, 104 
Willow bark, 106 
Wiltse's machine, 277 
Woods, 96 
Working on the beam, 237 

with the round knife, 496 



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